My wife is Thai, and my Brother-in-law has an ultralight over there. We go there about every other year. I checked a couple of years back when we were considering relocating there for a few years. Experimentals are prohibited except for the ultralights. I don't think you'll find many (any) RV builders because of that. I have not checked the regs recently, but there is a group of folks pushing to get experimentals approved in Thailand.
Transient is fine, of course. A few round-the-world folks have landed in Thailand, one in Phuket.
Have a good trip!