Yep, maps.me i used in past and couple of months ago in Wales. Recently couldn't find sat nag so grabbed tablet, slight problem only had map of wales (new sd card) so above advice load the area you need is vital.especialy if you have no means to on the move. used to have in van for a wider view than sat nag.Maps.me is a good free android app that will do as a sat nav on a tablet. Just download it and then down load the area's you need so it will work offline.
We found that and got a better USB cable which obviously pushes more power through so keeps it running much longer.It will have a GPS module in it. It will work fine. There are offline maps you can buy like TomTom Navigator free.
Only trouble I have had with tablets is that when navigating then they are power hungry and will run flat even when plugged in to USB. Google maps can seriously use data as well.