Most Versatile Discount on State Parks and MiFi Question

For state parks you can get Friends of the State Parks memberships for 10-20% discounts but they're only worth the cost if you stay on multiple trips; that and you would have to join the Friends group in each state where you plan to stay as the states don't have reciprocity on those memberships.

If you join Passport America you may be able to stay at a cheaper rate than National or State Parks. Researching the PA campgrounds along your route is your best option.