I wish I could say it is easy to set up that kind of a smartphone, but its not. It all has to be configured just right and then something updates and you have to configure it again. Osmand and Voice are the main problems. Your phone stops ringing when you get a call, so you have to find some obscure setting and reset it to what it was before.
We camped for a while without wifi, but then discovered we were driving into town a few times a week to get our email. The cost of gas was probably more than a data plan. We eventually got a unlimited 3G device, which was great until they shut it down.
While one can get by without spending money on data, it is a lot easier to have it. Of course then one becomes a screen time addict.