The one I like the best and use the most often is
Topo Maps by Phil Endecott. It's eight dollars well spent!
https://itunes.apple.com/us/app/topo-maps/id306014271It might not be the app with the most bells and whistles, but I find it highly functional and ver easy to use, plus with pre-planning (downloading the topo maps to your iPhone before your take off on your adventure) you don't need to have a data connection to use the maps.
For general fitness tracking, I currently use
Endomondo Sports Tracker:
https://itunes.apple.com/us/app/endomondo-sports-tracker-gps/id333210180I can't say it's the best (because I simply haven't tried a lot of its competitors), but so far I'm very pleased with the app.
.