As a fellow Minnesotan, I congratulate you on your wise choice for a vacation. As far as being solo, don't worry a bit. The majority of folks you will meet in the bars and tours are also tourists, and they are quite a friendly and outgoing lot. You should pick up some friends in no time if you wish. As far as the "ropes" go, not much to tell. Walk along the beach and if you feel a tug toward a bar or shop or tour outfit, just walk on in, everything is pretty loosely organized and there is no pressure. If you are the only one at the bar, talk to the bartender. Most of them are quite proud of their island and willing to talk your arm off. Check the board for favorite eating and drinking spots, check the maps for a general location, or just ask somebody. The downtown map makes things look a lot farther apart than they really are. Don't worry about strolling in single, your money is just as good as anyone elses
Check with the tourist booth in the square if you have any specific tours or anything you might like to see while you are there. Most of the tour operators put on a very good day for the buck.
Good Rum, definitely drink some Belikin. If you are a beer drinker, have them deliver a case to your room before you get there (if there is a fridge). Don't be afraid of trying different fish dishes, the snapper and grouper, stewed, fried or whatever is a real treat. Snorkel or dive Hol Chan. If you are a diver, or more adventurous, go out further, it is worth the trip. If you need some nighlife, check withg the locals to see where everything is.
Most of all, just don't worry. If you forget spomething, no problem. If it is necessary, you can find it. You can do as much or as little as you want with great ease. The only downside I can see is no lobster. I think conch may be out of season also. Other than that, have fun. Apparently you have more time down there than most of us, so it won't take you long to get out of the rat race. Island time is a good think.
Give us the rundown when you get back.
Unfortunately, I don't get to go this year.