Show up at bank prepared with proper docs (copy of visa, passport bio and stamp page, Thai phone number in your name, residence certificate from immigration and a copy of a long term lease will help). Dress professionally and ask with humility. Professionalism (preparedness and presentation) go a long way in showing respect.
You'll have 30 days to get bank account. Getting bank account is a 1hr process. Surely you can find a permanent place to live in 28 days, get a residence certificate and take copies of everything to the bank. Easy peasy. I think you're adding more stress than you need to but are on the right track. A month is a long time....