We were thinking of dividing our time between Thailand and Vietnam. Rather than getting the 0 visa and having to tie up 800k thb, we were thinking of entering Thailand with a 60-day tourist visa, extending it once for 30 more days, then spending the next 3 months in Vietnam and returning to Thailand with another 60-day visa + 30 day extension.

I saw a post saying that you can't spend more than 3 months in the country on a tourist visa within any 6-month period, so this route may not be possible? If this is the case, is getting the multiple-entry 0 visa the best way to stay longer? We would prefer not to tie up 800k/pp in a bank if we can avoid it.

We're US citizens, age 50+.

TIA.