Well, good luck to you with your search. I have two specific bits of advice for you.

a. If your guy is really a college student, then he's enrolled in college, and cannot simply take off 2-3 weeks on a whim. You will need to plan ahead, and co-ordinate your visit to coincide with either the shorter term break (coming in a couple of months), or the break between school years, which is also known as "summer vacation" AKA "the hot season."

b. This is not the right place to look for your guy. Try ThaiLoveLinks or other such sites.

In general, you should be on the lookout for scammers, and also be aware that many Thai college students do not speak English.