You must go see Casa Pueblo for a day trip. Beautiful. If you like nightlife, you must go during Dec, Jan or Feb. November (end of) is the time to relax at the beach (when it is nice - can be a bit chilly at times.) Beware of the intensity of the sun down there - no matter how well you think you tan!
Quick Tips:
You should know some Spanish here - a lot would help - but it can be fun not knowing what you are ordering or eating!
Very safe place, but like anywhere, dress as much like a local as you can and you will have a much better cultural experience.
Best Way To Get Around:
You really don't need to go anywhere from Esturion de Montoya if you don't want to. The beach is right there and the restaurant is fabulous. But, you can hire a "private" taxi like we did - he was at our beck and call all week - and is about per roundtrip - no matter if it is all day (go out to see Casa Pueblo!) or just a night trip into the main town to eat. Great deal for a great tour guide. (We tipped heavily.)