Kierjan, you can travel through Ha Tien to Kep / Kampot to get to Sihanoukville from Chau Doc without going to Phnom Penh, but it will actually take longer than going through Phnom Penh. So my question is why do you want to avoid Phnom Penh? Are you looking for speed or just a scenic route?
We recently travelled in the reverse direction from Kep to Chau Doc. It was fairly complicated and took all day, but for the most part (especially Kep to Ha Tien) it was quite beautiful. A tuk-tuk from Kep to the Vietnamese border was $15 USD, but to/from Kampot its more in the range of $25-30 USD. (A motorbike taxi should be about 1/2 as much.) The last few kilometres (or the first few in the other direction) are very rough and the tuk-tuk could not pass. The driver called two xe om (motorbike taxis) to come pick us up and take us to Ha Tien. I believe that the going rate for a motorbike taxi from the Vietnamese border to Ha Tien is about $4-5 USD; we paid $5 put they had to come several kilometres into Cambodia to pick us up. Mini-buses run fairly regularly from Ha Tien to Chau Doc (and vice versa) for 45,000 dong, but this is not a tourist-class service. Be prepared for a jam packed bus and a slow, bumpy, noisy ride. In all, it took us 3 hours to get from Kep, across the border, and into Ha Tien -- even though that's only about 35-40km. The trip from Ha Tien to Chau Doc was just over 3 hours, not counting waiting time at the bus station.
So you could do Chau Doc to Kep or Kampot in a single day, but you'd want to get an early start. The alternative would be to stay over night in Ha Tien - there are lots of hotels. Getting a xe om from Ha Tien to the border is very easy -- lots of drivers will ask if you want to go. From the Cambodian border to Kep/Kampot you could just wait and see if there are any xe oms around when you arrive, or better yet, see if your xe om in Ha Tien has any friends in Kep that want to come and pick you up. It sounds like many of the motorcycle and tuk-tuk drivers on either side of the border know each other, and have each other's mobile numbers! If you would like something more certain, you could see if a guesthouse in Kep or Kampot could send someone to pick you up, if you have any idea of what time you'll cross.
There are some regular transport options between Kep/Kampot and Sihanoukville, but I'm less familiar with those, as we didn't make that journey.
#2 amazon_blonde has been a member since 20/12/2008. Posts: 116