This is what I want to do, but as a husband, father, homeowner, etc, I find it is not in my best interest to be unreachable by phone.
So I think about carrying a flip phone for my telephone, an e-reader for entertainment, and a smartphone in airplane mode for (mainly) maps, photos, music, notes. But then I'd be carrying three devices, which seems worse in its own way.
Probably worth the change ultimately?
It drives me NUTS that nobody makes a decent e-ink device with a GPS app.
It seems like it'd be ideal for the backcountry use-case. Super long battery life because you could just wake up the GPS every few hours and get a new fix, reframe the map, then go back to sleep and use the latent image like a topo map.
I have a few use cases like this that would go towards replacing my phone. I'm on the lookout for a hackable/linux ereader.
I thought the reMarkable was that, but they hardware-disabled the Bluetooth radio in the wifi/bt chipset, and that really wrecked most of my use-cases.