My friend just did it and he said it was pretty easy just a lot of paperwork but like Dave said Boi is very helpful. I will apply at 62 if it's still available. There are two LTR groups on Facebook that I would join if I were you as they're full of experts and run by experts
DLT, Department of Land & Transportation is where its done. If really want assistance, Google visa agent near me. I have many recommendations but all in Pattaya