A pain in the ass. A bad idea. Maybe not even possible. I bring my truck over, but I own it and it took a long while to do it the first time. Better idea would be to cross over without a vehicle, and rent one on the other side.
She has a U.S. Passport, and entered Thailand on a 30-day tourist visa. Is it correct I can only get an O Visa outside of Thailand? If so, are there any financial requirements?