Vietnam (Hanoi) to Laos (Vientiane), Cau Treo crossing
Got my Cau Treo exit stamp in 09/98 in Germany (just ask for it), no problem.
Train ticket from Hanoi to Vinh is 128 000 Dong but if you are in a hurry take the mini bus to Hue (starting around 7 pm) tell the driver to drop you at the market area in Vinh (2 am) and take the bus...
In Vinh you start not at the bus stop you will find in the LP map but at the stop near the Vinh market. They charge 50 000 Dong for the bus ticket (Cau Treo is written on the ticket). The bus (the first goes around 6:30),drops you around 25 km before the border and heads to another destination. There is no direct bus. A jeep waits for you and in the middle of nowhere the jeep stops and one of the guys starts to bargain. We paid 3$ for the ride. For another buck at the border they skip the Vietnam customs. Walk three minutes to Laos immigration. Laos is easy, choose between Paksan and Tha Khaek. Pay the driver of the song thaew to Paksan to take you to Vientiane or take a Vientiane bound bus in Paksan. It's possible to make the H - V trip in 24-28 hours (some people do that!). Around 30$ alltogether.

Bolaven plateau: As many people visit the (mountain bikes at least one/day) try to explore the Khammuan Province. It's worth a visit.
Wat Phu: You can visit Wat Phu on a day trip from Pakse if you don't intend to go to the south. There is a boat from Champasak to Pakse around 1 pm (+ - 1 hour). They provide an excellent leaflet at the ticket counter at Wat Phu (1000Kip), ask for it.

Laos/Cambodia:
Border crossing at Kampong Sralau is not possible. [There is talk about reestablishing Highway 13 (connecting Route 13 in Laos with RN13 in C), so stay tuned.] Problem is the Cambodian side. Laos immigration let you pass (no exit stamp), but it's not possible (at least up to 50$) to get an entry stamp on the Cambodian side (assuming you have
a visa already). As usual, if you don't get an exit stamp your chance isn't high that the other side will let you pass.
Preah Vihear:
Open since 1.08.98. Take a bus to Kantharaluk from Si Sa Ket or Ubon (Warin 25 Baht Bus Nr.511). From here you can choose between taking a motorbike (driver, waiting time incl.) for around 200 Baht or take a song thaew into the direction of the border (which we did).
If you take the song thaew they drop you at a junction 11 km before the border (it is 33 km from Kantharaluk altogether). Then you have to hitchhike (easy). BUT 3 km before the border you have to leave a picture ID at a check point and the uniformed guys write the number of the car (most probably a pickup) down and connect the number with your ID. Which means you have to leave with the same car. So it's better to pay for the bike and it's up to you for how long you stay. Lots of food stalls near the parking lots.
You walk down the hill and after crossing into Cambodia you pay 100 Baht to get into the temple site. You are free to move, watch for the landmines signs. The area is heavily mined. The day we visited former KR cleared the area around the ticket booth !!(the whole program:from cutting down the veg, to marking the points). Walk up the cliff (in the middle on your right watch for the crashed helicopter). The view from the cliff is breathtaking. Preah Vihear will be a major attraction in the future, no doubt about that. Right now it's open on a try out" basis.
Khorat (Thail) to Siem Reap (Camb):
In a day, no problem. Taxi driver do the last part on the way from Sisaphon to SR after sunset this days. Cross the border before 1:30 pm and you can make it. I arrived at 8 pm at Smileys.

Angkor,SR:
Bar: the Steakhouse during 12/98 into 1/99.
Apsara dancing: ask at the dancing school down Sivoutha Str. direction of Phnom Krom (nice place for sunset BTW) or at Phreah Khan. When Preak Khan is illuminated by little oil lamps from the west to the east gate and inside of course on a clear full moon night and you walk through the temple area at 4 am, music in the background,and at sunrise the dancing starts in the Ta Nei: don't miss it. Between Thommanon and Ta Keo (near Ta Keo). It is safe, no mines anymore. Entry from the west, no restauration work. If you like Preah Palilay...then go to Phnom Kulen: Take a good driver (I can recommend Thra at Smiley, he really knows his way around),
try to go around the Banteay Srei checkpoint, then it is around 25 km to a few huts. KR are 1000 Riel per checkpoint. Expect around 5 of them (points). Going rate toget on the Phnom
is 15$. You can do it only on weekends. 10 of the 15 $ goes to the KR before you start your way. One or two guides, which are guards, accompany you all the way. Don't do it on your own.
You climb the hill, in the middle is a small temple around a spring, then it is around 4-5 km through the jungle, you cross a little nice and cool river, 5 of your 15$ you have already paid goes from one of your guards to another unit and than you can visit the Buddhist temples.
This area is KR aerea, you can see the results of the government bombings. From here it's a few hundred meters to an impressive waterfall (25 m?). On the way back you cross the river again. On both crossings you can see figures carved into the stone of the river bed. The area (temples and waterfall) is very popular, Cambodians are allowed to visit the place. Because of the landmines it's not open for tourists. Mines are the reason you get the guides, they make sure you don't leave the path (well, who would do it anyway?). On your way back ask your driver to take you directly to Banteay Samre (you circle Phnom Bok in a
way).
Boeng Mealea: Sorry, still off limits.

Battambang:
Take the Battambang boat in SR, leaving the Tonle Sap behind you follow the Sanger river upstream. Battambang has 3 bridges. The first you will reach is the one where you will find the SR-B-boats.
Hotel: Golden Parrot across the central market with a nice balcony from which you can watch whats going on (5$ with TV, 4$ without) and the spotlessly clean, modernTE.O (10$).
Restaurant TE.O, Heng Lim (3.Street), War Leap, Sbay Nas
Battambang has a Cham community, you can see two mosques from the boat.
Popular with the locals is Otaky where you can swim or rent a boat, 500 Riel to get in.
Visit Wat Ek Phnom. Wat Ek Phnom was used as a prison during the DK years.
The new Buddhist Temple near Wat Ek Phnom is under restauration.
Phnom Sampou: To visit the temples and caves on Phnom Sampou follow the road to Pailin for 14 km, climb up the steps. Wat Brahn is from 1964, Vimean Andet [WatKonping] from1968.
Ask one of the monks from Asram Tositaram (somebody should check the spelling) to open the temples if they are closed. The next pagoda you will see was used as a prison during the DK period.
Most of the people where killed by cutting the throats, a little hole in the wall directed the bloodstream out of the building. Around 10.500 people died here.
One of the two caves you will visit has the bones and skulls of a few dozens of the victims.
Look up when you stay before them and you will see that the cave has another opening.
Some of the victims were thrown down here (15-20 m) after their throats were cut. 300 m from this cave is another cave where you can see skulls, bones and clothes of other KR victims.
The other peak you see near Phnom Sampou is named Phnom Kdong. In the west is Phnom Banon, where a temple from the 12th century can be visited. My motorbike driver
called it a castle. Skip it.
Another 4 km into the Pailin direction you can see Phnom Krapeu which means crocodile mountain.
You have to look hard to see the crocodile covering most of the hill. Wat Andeuck (turtle temple) is a new modern temple at Phnom Krapeu mostly payed from rich Cambodians living in USA and Canada.
Between Battambang and Phnom Sampou is a temple from the 11th century on your left site. I did not try to visit it, the tank beside the temple changed my mind (although most of the soldiers slept in theirs hammocks).
Back in Battambang follow RN 5 from the bridge around 1 km to the airport, take a turn to the left and after another 5 km you will come to the Baset temple (11th century). Ask your driver to bring you to Tapon (Sanke district).

Pailin:
Frontseat is 200 Baht oneway B/P. If you want to stay tell the driver to drop you at the Sang Phi Run Hotel. It's on the way to the market where the taxi stops, so you don't have to go back (uphill). The hotel is nearly opposite the Caesar International Casino which is a bit smaller then the one in Vegas. It is also only a few hundred meters from the
temple site.
Border crossing is not possible, this time the Thai side is the problem.
Locals commute from and into Thailand but for foreigners it's still closed and most probably will be closed for another few years. How the suspension bridge on the way to the border survived all the years is a mystery. If somebody tries for real to get Khieu Samphan and Nuon Chea out of
Pailin avoid the area. Right now everything is peaceful and it is worth to visit for a day or two. If there would be trouble again they will get you out of the car or from a bike in Battambang or at the checkpoints. Once you have crossed the Pang Roloem ckeckpoint you are inside Pailin.

Battambang -> Sisophon:
Good road. Afterall, in my opinion to reach Sisophon from SR it's much better to take the Battambang boat and proceed by car to Sisophon then to go the way directly.

Vientiane:/Nongkai border crossing
Visa on arrival at the friendship bridge is 30$ weekdays 31$ weekends.