I use Google Maps on my phone. If you don't have cell service you can still see and use the map, but the dot showing your location won't move.
Beware that NO mapping service is perfect, especially on roads in rural areas, national forests/parks, and state parks. Carry a good state road map for backup and get park maps if you can. These are also helpful if you find a road closed or some other detour. Use your common sense and don't go down a road that looks "iffy" even if the mapping service tells you to.