West and northwest of Kanchanaburi city are several of Thailand's largest waterfalls and most extensive wildlife sanctuaries. Most of the province, in fact, remains sparsely populated and wild. - from Lonely Planet I have been to this province a few times before, and all I knew was Bridge over River Kwai and a few golf courses around the city. The city - Kanchanaburi is 130Km from Bangkok. From there you have to take route 323 westbound to Sangkhlaburi. Its easily 3 hour drive distance.
Road is nicely covered but a few section is still under construction.
In general any kind of vehicle can go to Sangkhlaburi. Its beautiful drive way with great scenery. The small town has great wooden bridge built by Mon tribe living there. The bridge stands like an enormous monument. On the trip, I really wished to bring some friends to enjoy some small adventures together.