We're moving to the Kingdom at the end of November and are applying for retirement visas with a multi-entry permit. We'll be renting a condo for at least the first year but we were unaware that we'd need to inform our landlord of our movements.
Book a hotel that falls within the 60 days that you'll be in the Kingdom in Cambodia, Malaysia or Vietnam with full cancellation rights where you'll pay at the hotel and tell the airline you'll be leaving Thailand by train, boat or car.
Once in Thailand, cancel the hotel booking. Ta-dah!