Buy a used smartphone and load Back Country Navigator via wifi. you can save topo maps that work offline, claim boundries and tracks to the claim - for a lot less than buying a gps. Also you can load a find-my-car app too.
I have found the WM 12 can slip off your belt or harness easily when bending over - be careful. I've also run with a rattler headset plugged directly into the GPZ and the WM12 on my belt - primarily because my wife said it was not fun if I just used the headset and she could not hear anything.
I was able to upload claim plots to BCN using GPS Visualizer.... not 100% accurate but close enough if I don't stay near the borders. Also saved BCN Map so I don't need data connectivity. I tried Gaia maps for android too - and what I like about their maps is that I can switch from TOPO to Satellite, to road maps.