For camping, I like Allstays Camp & RV
best because of the "open all year" filter. Lets me find off season campgrounds. Although I don't use them as much, I also have Camp Where
which lists public campgrounds & provides links for reservations covering the US & Canada, and RV Parking.com
As to non campground apps, I have far too many to list all of them, but some of my favorites are Pandora, Gas Buddy, The Photographer's Ephemeris
(although designed for photographers, it is also useful if you want to position your trailer to favor alignment for solar
- it shows sun & moon rise/set times & directions for any date on a Google map), Public Radio, Coverage?
(Maps of cell coverage down to street level for all the major providers), All Trails, iBird Plus, MyRadar,
and iHandy Level
Fotopedia's National Parks
has thousands of beautiful photographs of all US parks as well as park maps, etc. I also like the iFhotoGuide
& the Chimani
National Park apps, although they do not cover very many of them.
I'll stop now!