I use an IPhone but some of these may also be available for Android. Most are free but some cost a dollar or two.
Oh Ranger! Park Finder: Easily search for public parks. Each park has information about camping, hiking, picnicking, and other activities.
Passport America: Easily search for Passport America RV parks. Each listing shows the address, phone number, rates, and amenities.
RVParking.com: Choose a location and see a map showing all the campgrounds nearby.
RV Continuous Traveler: Search by location and see a list of RV Parks nearby.
Recreation.gov: Search for federal campgrounds, see descriptions of the campgrounds and make reservations.
Chimani National Parks: Lots of information about National Parks
Pocket Ranger for Georgia State Parks: Information about Georgia State Parks. Apps also available for other state parks.
Road Trip: Great for keeping track of fuel and other vehicle expenses.
GasBuddy: Find gas stations and gas prices near you.
Waze: Tracks your route by sattelite and gives you current road condition updates including police, accidents, traffic.
i Exit: Shows where you are on the interstate and what services are available at each exit