Feeling accepted

That really depends on you and how rigid you are.  The fact that you are trying to quantify the experience of exploring a new culture and putting time limits on it suggests you may have a difficult path ahead.

I’m very easy going and have no rush in doing anything.. I do not like pressure and love to learn other cultures just wondering if a guy from Minnesota that’s retired can live there in peace and a not have a time limit . Tranquil and happiness is what I appreciate most.

These kinds of questions are like asking how long a piece of string is.  Each piece of string in different.  If you are easy going, peaceful, tranquil and happy where you are, then you will probably be the same person here.

I am that my friend, always relaxed but also very cautious

Yep, it takes a long time to learn any language. Depending on how much you need it, the faster you will pick it up. It certainly helps to begin chipping away at getting a solid foundation in Thai literacy. As for the do's and don'ts . . . that depends on who you are hanging out with. Exercising respect for your host nation and using good old common sense is a step in the right direction, I think. Understanding what the flag symbolizes helps to give perspective in a broad sense. One step at a time -- usually. Leaps and bounds -- more rare, but it happens. Best,  dcb

Language takes as much time, as you are ready to dedicate for it! But defineteley, it's easier to learn all cultural details, "do not" and "can do", what is impolite and how to be polite with locals. You better make friend with Thai to learn this with them, some things you will never know from foreingers or by yourself (like its extremely rude to point with foot)

In general there's not a long list of things that you can't or shouldn't do in Thailand, or that are going to offend locals.  Thais aren't touchy about most things.  You shouldn't point at things with your feet, or use them to close doors and such, touch people on the head, or show anger in public. 

Those are just examples, but they point towards how easy it would be to avoid most of what seems problematic.  If you did close a door with your foot, show anger in public, or touch someone's head they'd let it slide.  Completely integrating culturally is a different thing; that would take some time.  Most expats don't even try to get to that point but someone well suited for it living under the right circumstances could get pretty far in a few years.

Learning the language is a different thing too.  Learning any foreign language would take awhile, and it's common to run across the idea that Thai isn't easy to learn for an English speaker, as French or Spanish would be, or as hard as more difficult language like Mandarin would be.  The tones are tricky, and learning any foreign alphabet takes some doing, but the structure of the language is simple, without a lot of different word forms to memorize (cases / tenses / conjugations).