Hadn't heard that PC is a big spring break destination... but I guess just about anywhere is these days. To get any kind of real local flavor, you'll have to get outside the resort. The people at the resort, the reps from the travel agencies, etc., etc. will warn you over and over not to go outside... using scare tactics to keep your $$$ being spent inside the resort or with their co-op tour operators, excursions, etc.
As a former AI guest, and now a condo owner in PC, I CAN TELL YOU IT IS PERFECTLY SAFE to venture outside the walls of the compounds. Exercise the same basic cautions you would anywhere in the world, (including your college campus), and you'll be fine and have a great time. These are FANTASTIC people who are friendly, forgiving, and will (for the most part) treat you fairly.
The AI's are spread out along the entire coast of "Punta Cana" (35 miles), which includes a number of other areas. The "town" of El Cortecito is pretty much the center of things, so you might want to look for the AI's that are in that neighborhood. You can also now rent condo's, (not mine... it's not done yet. LOL), which include an all-inclusive package. This is something new which I just discovered myself. You can find out more about that at CheapCaribbean dot com.
Whatever you decide, I'm sure you'll have a great time. It's hard not to here. Just remember this is not the USA, it is a different country with different customs and different sensibilities. Go with the flow and enjoy your adventure!