antigen test is sufficient to USA.worst case scenario they have it in the lower terminal level of the airport,,give yourself time,,,if you don't get it done until you reach the terminal
I can go to hospital on my own for 2nd test in HuaHin and then report to the hotel for check-in right after, or get transportation to hospital and back for an extra fee, but staying in room is required until 2nd test result..
when you start filling in the thailandpass you just need to follow the instructions of what to do when they ask for hotels etc, very simple and instructions easy
sealed flights will only show up in availability if booked as a direct connection from an intl inbound flight to bkk,,,,so just looking at bkk hkt will not be enough,,,