Get in touch with these folks:
http://www.servair.com.do/en/p/airports/sdq-mdsd
They will help you out with anything you need, weather, flight plans, fuel, anything you need. Remember that if you are going to do any domestic flights in the DR with an "N" registered A/C you will need to file a flight plan even if it is under VFR. As to single pilot ops it is as any other ICAO member state, so the answer is yes. There are a few Dominican pilots in Florida (studying, getting ratings, working in jobs here in the US) if it comes to you wanting somebody to go with you and help you out, let me know, I'll hook you up with a side kick. Haven said that, you won't need it, servair will give you all the help you need.
Hanging out at night in the DR, well it really depends on where you go, if you are going to a resort, you are fine inside the resort no problem, if you go out clubbing or something in Santo Domingo, make sure you consult with a local or go out with a local, it has great night life but it can be dangerous if you don't know what is going on.
Enjoy my neck of the woods dude, let me know if you have anymore questions