I went to an on-line map that draws radius circles from any point. I focused on Central NJ and went out 200 miles. (about 4 hours of towing time at 50 mph).
The spot that grabbed my attention first within that 200 mile radius was Hershey, Pennsylvania. You've got the Hershey factory and amusement park there. You are also well within reach of Washington DC, Gettysburg PA, and Baltimore. You are still within reach of Amish Country (Lancaster PA).
Actually, considering you are traveling with a pack of girls, I would ask them what they are most interested in seeing and doing. "Shoping" is not a good answer. (Actually, underground Alexandria Virginia is an interesting shopping area, and close to Mt. Vernon and Fort Belvoir). The next question should be "Where?" and keep drilling down till you get a specific destination.
For example, if the conscientious was American Girl Doll's, the location would be Middletown, Wisconsin, because that is where their corporate offices are located. If their interest is Chocolate, then definitely Hershy Pennsylvania. A simple Google search on their subject of choice and you can pin-point down a location rather quick.
We once did a 10 day trip all around Indiana. We hit every railroad museum in the state. We moved to 3 different locations to make it happen. But it gave us destination points, and something to do while there. Actually, that was one of our better trips too.