I wanted to add a current review for the Allstays Camp & RV app. The app is now $9.99 but in my opinion, it's a bargain.
We bought a Samsung tablet for our last trip. We don't have a smart phone or any kind of mobile hotspot. If we wanted internet, we had to find a "free wi-fi" place to connect. Even without internet, I still highly recommend the app for anyone with a GPS-enabled device.
Here's what you get with the app:
1) Your GPS location on a map. You can zoom in and zoom out on the map as well as navigate around the map - like Google maps. If you aren't connected to the internet, you'll get your location on what looks like a piece of graphing paper.
2) Just about every kind of campground you can imagine: national parks, state/provincial parks, national/state forests, county/city parks, public lands (BLM), Army Corps, military, Moose & Elk, KOA & private, and a variety of overnight parking options (Wal-Mart & casimo parking lots, etc) - pretty much everything except your in-laws driveway. You can filter for any or all of these to show up as "points" on your map. I'm not going to promise that it's 100% complete or 100% accurate, but it sure does a better job than any other camping guide/directory I've used.
The app also includes filters for various things like rest areas, stores (REI, Gander Mountain, Dicks, etc) and truck stops (Flying J, Loves, etc)
3) Select a data point and a little information window will pop-up with some general information about the location: facility name, address, phone number, general driving directions, and general information (open dates, # of sites, camping restrictions, water, toilets, showers, dump station, laundry, etc.) Everything is linked to GPS coordinates so even without an internet connection, all of this off-line data is still available.
4) If you are connected to the internet, there are side buttons you can select which will take you to the location's website, plus images and reviews, if available.
For example: even with no internet access and a bunch of data points on a piece of graph paper, it gave us near-by alternatives to an expensive Wisconsin State Park - with the general driving directions and our (paper) state atlas, we were set.