I was just at the Grove City outlets on Saturday. We're in that area a few times a year for other reasons, and I always make a point of stopping at the outlets. I like them way, way better than the Niagara Falls outlets. You can see the full list of stores on their website -
http://www.premiumoutlets.com/outlets/outlet.asp?id=85 - and they have some of the special sales and offers listed as well. You can usually get a flyer at your hotel to receive a coupon book at guest services, and it's worth the effort.
There's a half a dozen or so hotels nearby, including most of the major chains. We usually stay at the Holiday Inn Express. It's not really walking distance like a couple of the hotels, but I prefer to drive over anyway so that bags can be dropped off in the car at intervals instead of lugging them around - the mall is huge.
Our favourite restaurants there are Hoss's (like a Ponderosa, if you remember those) and King's. The outlet food court is okay if you just want fast food.
The most important thing when booking a hotel is to make sure you are booking Grove City PA - there's also a Grove City in OH, and I have a friend that made that error once and then couldn't get a room because everything was full.
I personally wouldn't waste the time heading over to the "real" community - not enough there to make it worth the 15 min trip. The
Walmart at the Peach Street exit in Erie is way better, and that exit in Erie also has a Target, Giant Eagle and a ton of other stores and restaurants, and it's a pretty short drive to the Millcreek Mall if you have time. On a long weekend trip, we'll generally do Grove City first, then stop in Erie on the way back. We often split the hotel stays, with a night or two in each place.