There are places where signals are available and others where there are not. The digital TV signal (actually it's the UHF frequencies) is weaker and must more easily blocked so even different sites in the same State Park will get different results.
The Batwing antenna with Wingman add-on (or the Sensar IV if you need a new antenna) will give you the best chance of reception. If you like to watch TV, I highly recommend that you bring your DirecTV box with you and purchase something like the Winegard Carryout antenna which will provide fully automatic reception of the DirecTV signal without the hassle of setup. The only restriction is that this type setup will not allow for the reception of the HDTV programming but the SD versions are still way better than no TV.