Rent a Bike in Thong Pha Phum and go up the National Park, Pha Phum. A delightful tour though dens forest up to Knife Blade Ridge mountain with a great campsite. Then to Pilok at the Myanmar border. Nice trip, nice people, some days you meet a lot of Thai Bikers there. The Bike you can rent is not worth mentioning, but maybe that will change over time. Good time is November December, less rain and nice temperature. Bonne Route
I know this area really well as I've spent 5 months everyear staying in kanchanaburi,I ride all the trails out there with Thai enduro riders and we camp in the jungle,I have a house there and 2 enduro bikes if you are ever out that way again,thong pha phum,pilok,sangklaburi and sai York are beautiful rides either on or offroad but the scenery is spectacular when you get off-road.cheers,jez