My life is very similar to yours. I have been here 3 months already. Agents DO make magic happen. For sure get a bank account open and some $$ in it. There are many good visa options for 50yo. You can be a rock star here on your income. Enjoy!!
Keep your USA phone with a cheap plan. You will need it and it makes life simpler. Get a thai phone and number here at the mall. AIS or any of the top 3 carriers.