Or, you could just get the new non-smart phone and keep any old smartphone unactivated, with no data plan. The trail maps would still work just fine without a data connection, so it would be free. Consider it like an ipod touch, smartphone functionality when on wifi, but no calling.
On the bright side, such a device would preserve the ability to call 911 in an emergency, because that always works even if your device isn't activated and has no plan. On the down side, you might be tempted to download twitter or IG or whatever else you're trying to get away from.
These days, I don't think it makes a whole lot of sense to think you can isolate yourself from technology just by trading in your smartphone for a dumbphone. Are you also going to avoid tablets and laptops? These devices also do all of the same things, though I think a tiny deactivated smartphone is the ideal device for hikers who want trail maps.
I also like the old LCD etrex GPS units, which are not much heavier and have much longer battery life, but the screens are terrible and it will take you forever to learn how to use it efficiently.