Azza, I think the important thing is to try and not get bogged-down in the smaller stuff. I'm 18 months in and nothing here is set in stone for me at all. I know we all like to plan things as best as possible but the focus should be on dealing with organising things at home, not Thailand. Thailand is the easy part.
The important things to get sorted are back home in order to release yourself from your western life and ensure you have sufficient income to support yourself after the move, either with or without working, that choice is yours. Also a will, trimming unnecessary bank accounts, credit cards, dealing with taxes, standing orders and debts, if any. Also ensuring bank cards are up to date for maximum life and daily withdrawal limits set to maximum, for emergencies etc..
What happens in Thailand can all be dealt with once you're there without committing yourself to anything too much in any direction, at least during the initial months. I would always recommend 100% to rent somewhere for several months at least to see how it feels. See what the area and it's conveniences and inconveniences are like and whether they are manageable. You will have so much time on your hands to wander off checking out other areas or accommodations should your short-term rental not be what you want. Freedom without commitment, at least in the early stages.
I understand what you mean about creature comforts, but realistically you'd have nothing more than a manageable amount to pile into the back of a hired songtaew should you choose to move. Ultimately further down the line you may choose to buy a condo or suchlike, that decision is yours, but you will have made a much more considered decision if you'd already spent months on the ground first.
