1

Welcome to the Thorn Tree's Thailand branch.
It is highly recommended that new users check out the Thailand FAQ thread before posting a new thread as you may find many of the answers you seek there. It also contains helpful information about how to search the forum and advice for how to post your questions to obtain the most useful responses.

2

Buy a guidebook and also learn to use the search function. Thousands of people have done (and are doing) what you plan to. Good luck and come back when you have more specific questions.

3

Yep, I did a similar trip on my own about 14 years ago. I arrived in Bangkok, met a few fellow travellers, swapped stories then took it from there. Ended up going north and into Laos for a few weeks then flew to Hanoi and spent a month in Vietnam, came to Phnom Penh and Siem Reap then flew to Bangkok and went to the islands. Ended up in Malaysia on the Perhentian islands, flew to Borneo, climbed Mt. Kinabalu, went caving in Sabah, flew to Johor went diving at Tioman island got head-butted by a trigger fish, etc. etc.

The point being, sometimes it's best to just let the adventure unfold. Save some money, get a flight and maybe a couple visas (Thailand and Vietman) pack a small bag and go for it. If you have specific questions meanwhile fire away! Thousands of people do the classic SE Asia circuit every year so you'll have loads of company.

4

Thanks folks, I'll get a few travel guides and do the rest of it off the cuff