We just got an InReach Mini for checking in with loved ones, and for SOS emergencies. We'll probably use the preset messages the vast majority of the time, and use the least expensive plan ($12/mo). We have mountaineering friends who have been rescued (and helicoptered out). The way the InReach team communicated with them was really a positive experience.
Gaia is the best maps app, in my opinion. The InReach is not very good in comparison, which uses the phone "Earthmate" app from all I can tell so far. Gaia works great on iPads in the truck and on the phone. Gaia is a little expensive compared to most apps, but worth it if you want USGS maps or a whole array of other map choices (including Forest Service and National Park maps).
We also download areas on Google Maps app on the phone/tablet for areas that are out of cellular range. It's great for driving and can even do driving directions (but not walking, cycling, or transit directions) off line.
I also use my hiking GPS for yet another electronic map backup. But gradually just using the phone (poor battery life) and the GPS is used just for tracking our route (batteries last all day, can be replaced).
Geez, all these electronic gadgets! Lewis and Clark didn't have all these hassles.