I apologize if I'm duplicating info here because I didn't read TFA or all the comments, but the resources I've use are the offline maps in Backcountry Navigator

I apologize if I'm duplicating info here because I didn't read TFA or all the comments, but the resources I've use are the offline maps in Backcountry Navigator (paid), ViewRanger (free), AllTrails (paid), Maps.me (free, no topo info, but a surprising amount of trails). If bought custom waterproof maps from mytopo.com and I've downloaded maps US topo maps from https://ngmdb.usgs.gov/topoview/viewer/ https://ngmdb.usgs.gov/topoview/viewer/ and then had them printed at Office Depot (at a readable size, but not on waterproof paper). Having multiple sources of truth helps, and also I've had glitches downloading maps offline that I didn't discover until I was on the trail, so the offline maps of apps back up each other. And also I've used Guthook for the PCT, which is wonderful. I'll add that I carry an extra battery anyway to power not just my phone but my Kindle and my Garmin Inreach Mini.