Anytime will be a good move from USA to Thailand. If you can do it now do it now. As a couple you pretty much need to figure out what you both wish to do with your retirement but wouldn't recommend Pattaya. My missus quite rightfully said Pattaya wasn't an option for us due to the temptation that faces men in that city.
I'm Aussie but 3kusa is a pretty decent budget here. It's around 100k baht a month. When I was single half of that was my living expenses and the other half I spent on girls. You could spend less on girls but I loved soi6 girls mostly so paying a few drinks, room cost and the girl came to around 2500 baht or there abouts. But you could still get fit freelancers for 1500 to save a bit more. So even though Thailand is more expensive these days, 100k a month is still a good life
A tm30 most likely although might not be the case for a tourist visa but definitely check with someone on that as immigration love stinging farang with their 1600 baht penalties that are supposed to be the landlords fine