So here goes. 
Palmas (as we call it here) is a nice place to live. There are many expats living in the area and I'm sure you'll find all kind of activities. Here's the website with a lot of information :
In our area east central Puerto Rico this is the only place that fits your descrption
Interested in living in a nice, fairly upscale, safe place not too far from Los Piedros/Juncos area.
Oh, by the way it is Las Piedras 
The contrast between Palmas and the 'outside world' is rather big. The real Puerto Rico is outside although I must admit that Palmas is a nice place to be. We visit every now and then - friends from the mainland own an apartment - and there are some nice places where we hang out every now and then.