I haven't tried Lifetime Trail Maps but I have used BackCountry Navigator with Bob T's maps. I bought a refurbished Samsung Galaxy Tab A 10" from Amazon for $110. $15 bucks for the BackCountry Navigator app and of course Bob T's maps are free. I use a computer everyday so I didn't have trouble setting it up. The app is very powerful so that means it is not always the easiest to use... best to practice on local trails for a while until you get the hang of it. Make your own tracks, save your waypoints, etc. On local trails you know. If no trails - get in the car and drive around on local roads, the point is to learn how to use it before you need to rely on it.
Basically what Bob T's maps are is a collection of waypoints and tracks for the locations he's documented. West Virginia seems to be the most popular. They overlay on top of the terrain the app shows you. You can turn all waypoints & tracks off, and then just turn on what you want. After making your own track you can export it to share with others or to preserve it. The Google Earth app on a computer can open these tracks so you can look at them later.
I put mine in a Ram mount with a 1.5" (C-size) ball since its such a big tablet. The 10" tablet is a little on the large size. I started this in my Wolverine X2 and now I'm moving it to the KRX where there is so much more room, the 10" might be ok. I've often thought if I were doing it again I would do a 7" or an 8".