I think using an agent is best. Sooo much easier and faster. I'd look at the visa subforum on aseannow.com for very good help.

 

I recommend using an immigration lawyer. I have heard good things about Siam Legal. Ask them for a consultation about your visa situation.

 

If you can read, you don't need a lawyer or an agent. The rules and options are pretty simple. There are two kinds of visas for you: Non-Immigrant "O" with Thai wife and Non-Immigrant "O" retiree. To qualify for the marriage visa you will need to have THB 400,000 in a Thai bank when you first apply. For your first annual renewal you can maintain the THB 400,000 or use your bank bank records to certify that you have been receiving at least THB 40,000 each month without fail by international money transfer after which you won't have any minimum amount to maintain in the bank account. For the retiree visa, you have to show THB 800,000 in a Thai bank at the time of your first application. At your first annual renewal after than you can switch to the monthly deposit method if you have been contributing at least THB 65,000 per month by international transfer without fail.

You will also have to do 90-day reports online, by mail, or in person.

The retiree visa is more convenient. For the wife visa you will have to take your wife with you to each annual renewal and you will have to make a second trip to the TM to pick up your visa a month after your application. Neither requirement applies to the retiree visa.

You should open an account on thaivisa.com to post your questions there.