Bangkok is one of the paridises in the world. They have everything for backpackers. Gentle and kind people, amazing and mistic wonders in the nature. We can try all of them with no bother of money. Full of food and accommodations, comfortable restaurants...
taking a nap on his bicycle in Chiangmay
Chiangmai, for one or two days trecking there, you can experience more than you can imagine. Baboo rafting and elephant riding, sleeping in the cabin with tribes is another great experience.
What's really great:
snorkeling in Pipi island
Ko pipi island in southen part of Thailand is one of the most beautiful ones in thailand. Snorkeling in the bamboo island is the fantastic. You can see thousands of colorful tropical fishes.
Peachy guest house is one I used to stay. It's near unicef banglampoo Bangkok.
Kanchanaburi trecking including River Kwai is great one, too.