First start with 60 days touristvisa + 30 days extention, the no need to leave Thailand in 90 days.
Then go to other countrys.
When going to Thailand for 31 - 60 ( 90 )days, the 60 days touristvisa is the best option.
It is cheaper than visa excempt + 30 days extension.
No need of a onward ticket ( 90 days 1 onward ), if returnticket within 60 days.
It is easier to apply from the comfort of your home.
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Not wasting holiday time to find, go to and waiting at a immigration office ( 90 you would need that ).