@Derrick *******
Your previous post said you were looking at staying 3-4 months. If you have to enter visa exempt without a visa, then you'll only be able to max out at 75 days (45 days visa exempt + 30 day extension).
So if you want to stay 4 months you're going to have to do at least 1 border bounce. Based on the location you gave in your previous post, there's not going to be any convenient border to where you're staying so it's going to be a long trip. Most likely you will want to just fly to another country and then stamp in and fly back to Thailand. Many options including Singapore, Cambodia, Malaysia etc (maybe not Vietnam since they require a visa for US citizens).