I've just got 90 day "retirement" visa from London. So that, go to Thailand and take it from there. You should be able to open a bank account with that visa. The rest will depend on the requirements of immigration office in the province you plan to stay in
Yeah. I used to live in Thailand and did the annual extension of my stay based on my monthly income. I find the 800K in a Thai bank account as very harsh. I simply can't do it.
I went over with 1 suit case and that was too much. Only need to take personal items you can't get in Thailand. You can buy most things you will need or rent a fully furnished condo/house.