Some more details may help. You don't mention if this is your house or condo, or if you will be renting a place. Much of a solution will hinge on if the place has some kind of broadband already wired into the building. If it does, then you have to find out which company controls it and approach them to see if they offer a short term plan.
Concerning the SIM card approach, I can't 100% confirm but I think TRUE has an unlimited data package for about 800-900 per month. If they do I'm sure AIS and DTAC have as well. I hesitate a bit on the "unlimited" part, but I think it is. Pete
