I have just done the same thing in Nong Khai. The account was set up in Udon Thani. Whent into the Nong Khai branch and asked to change address on my account. No problems, and they were very helpful.
As a single guy I live on around 45,000 bht per month in Nong Khai. I enjoy the quiet life and going to local Thai bars for a few beers. Also do a bit of travelling around. It all depends on the life style you want.
From what I could see it's 23kgs check in. 7kgs hand luggage within the size limits and one extra small carry on bag free. I assume this last item would just be the sort of small bag you would carry your document's in.
Just did Bangkok to London a couple of weeks ago. Did the electronic check-in which made it easier at the airport. Just had to drop bag off and that was it. As for seat selection I didn't bother as flying alone, and personally not bothered where I sit.