For the time and resources available the app is currently at its limit on storage to work with various devices. I'd imagine it will change in the future but do not see that happening any time soon.
If you are in cell range you can always set a new route to follow which loads the maps.
If you plan ahead you can make a route with up to 400 miles. A "route" is a collection of tracks and waypoints. So for instance you could have twenty 20 mile hikes. You can do all of this on HAZ using "Route MGR", then save to "Route Cloud", then import on "Route Scout".
around 11:48 in this video mentions basics for Route Editor
[ youtube video ]
to make it really work you need to fully understand Route Editor, the tutorial is at [ youtube video ]