I am a US citizen. I plan on getting a 60 day (1 entry) Tourist VISA at the Thai Embassy here in Los Angeles. Am I correct on assuming that if I leave Thailand on say, day 45 to visit KL for a weekend, that the VISA will be cancelled when I leave for KL and when I return to Thailand I will get a 30 day passport stamp? This way I can avoid the extra charge for a 2 entry VISA.

Surely, you can even leave on day 60 for KL as planned and get a thirty-day on return.

If you leave on day 45, then your Visa is finalised. You then return a a "new" tourist and get your 30 days visa exemption upon entry.

Why not just come with no visa get a 30 day permission to stay and leave on the 29th day. Fly out and fly back for another 30 days. Or better yet get your 60 day tourist visa stay for the full 60 days and extend it for 1000baht and get another 30 days with out leaving the country.

I'm not going to KL to get extra days added to my visit. I'm going there because I want to see KL (like any other tourist). If I just wanted some extra days beyond the 60 day VISA, I would just file for an extension in Bangkok.

Why not just come with no visa get a 30 day permission to stay and leave on the 29th day. Fly out and fly back for another 30 days. Or better yet get your 60 day tourist visa stay for the full 60 days and extend it for 1000baht and get another 30 days with out leaving the country.

Without a Visa or an onward flight within 30 days he could be refused entry on the flight in U.S.

Extensions at Immigration cost 1,900 Baht.