This is address on Immigration. If you write it in google maps (It square laksi )this is big trade center on 3 th flor can get there by BTS and change to train. They will tell you what you need. If you have something wrong they never will take your documents. Most important is Address if you do not have TM30 can pay to same Hostel 100 per night for fews days they will do for you TM 30. Good Look !!!
Last year I was in Thailand on a tourist visa from November to February then I returned to Thailand in April. I went to Vietnam for 10 days in May I returned to Thailand and then in June I went to Japan then I returned to Thailand again. You will not have any problems before you fly in the airport there is a re-entry counter you have to pay 1000 baht and submit one application it takes 3 minutes if your application is ready Mine was ready on the computer, I just changed the dates. I think you should also include a photo. When you return, they will stamp your passport as long as your last stamp was valid. They don't ask any questions my 60 day stamp was expiring in 4 days when I was coming back from Japan they just told me it expires in 4 days I said I know. When I arrived I got another 30 days from the immigration office. The tourist visa is the best visa because you can travel freely and you don't owe them any explanations.
I thinking to do this :you can apply for non-o over 50 in Kuala Lumpur, you just have to prove that you have the money somewhere, then you come to Thailand (90 days entry stamp) and immediately open a bank account and transfer the money, after 2 months you go to the immigration office to get a 1 year extension