Kanchanaburi seems like the big city after most of the places I've been in Laos, but it's pretty small. Reasonably free from (Western) tourists, it's the location of the infamous Bridge on the River Kwai, part of the Death Railway. Tons of Japanese tourists here to see that, they come and go in huge tour busses.
The surrounding countryside is lush and green, with waterfalls and caves all over the show. Look through the photos for some idea of the place.
Places to stay: I stayed at the river guest house, which features rooms on stilts in the river at reasonable prices. While the colour of the paint is questionable and the river portion it's in isn't the best, 150 baht a night is pretty good, the rooms are a decent size and you do get a private bathroom with that.
Places to eat: We pretty much stuck to market food, but Kanchanaburi is a cheap place for just about everything, so you can't go too far wrong. Most guest houses have their own restaurant, check them out.
Things to do: Hire a motorbike and check out the countryside. The big chinese temple to the south, name of which I cannot recall, is really cool; check out the photos. Erawan waterfall is meant to be great, unfortunately we didn't make it there (it is about 60km away, so be prepared for a long ride). There are lots of Wats, waterfalls and caves to explore.
No locations available.