you can authenticate your line with passport and then access all options. You can to do it at bts station as far as I know with rabbit card that’s what I did 3 years ago
I guess this extension is just theory, best is to go somewhere and come back, same price as an extension and you’ll need no paperwork and can enjoy a nearby country :) a trip to Vientiane by train would be super cheap and nice to do (Richard Barrow’s Thai Train Guide will give plenty of info on his website)
I read that someone got DTV by showing his properties and real estate contracts, screenshots of exchanges with tenants, letter of himself explaining he manage his property remotely and can do it from anywhere
