Springtime in the Park in Hershey is a very good deal. Obviously, the water rides won't be open, but all of the coasters and the majority of the rides will be, so it is definitely worth the money.
As for places to stay, Hershey hotels will be a lot cheaper than Philly. There are plenty of chain hotels in the Hershey/Harrisburg area. I would look at those before the Hotel Hershey or the Hershey Lodge. As for shopping, the Hershey Outlets are just down the road from Hersheypark...less than five minutes. There's a Red Robin (burgers) next to the outlets, but if you like seafood, there's a great new restaurant that just opened in Hershey called, Devon Seafood Grill. I've eaten at the one in Philly and it is fantastic.
Obviously, in Philly, everything is a little more expensive, but you can still find some good deals. Honestly, it's the parking in Philly where they really get you...$25 a night!

That being said, if you want to stay downtown, expect to pay about $100/night. I always use Hotwire when we stay in Philly and have gotten fairly good deals.
There are lots of freebie things to do in philly with all of the historical attractions, Liberty Bell, Independence Mall, etc. I aways reccommend people visit Reading Terminal Market. Lots of great eats! Check out
www.visitphilly.com for more deals and things to do.
Enjoy your trip!
