Get a SETV from a nearby country while travelling South East Asia.
Takes maybe a day of your time out of your travels.
Laos is the best no documentation needed.
Other countries you might need to plan a little and prepare some docs, get a week of accomodation lined up (use agoda and find something with pay at property and have a cancellation period), book flights (ideally with a free cancellation period), and sometimes they might ask for a bank statement.