I could be wrong here, but...

-While you may be able to cache GMaps (offline mode), I don't think that the phone will track you unless you have access to the network.
-You will also be draining the battery while tracking your route, assuming you manage to do that without a data plan in the first place.
-AFAIK, phones don't really have true GPS. The ones that feature Navigation do so using triangulation of your position in relation to the cell towers.

You might be better off with using a tablet to cache your maps on and make then consult that from time to time. At least if you find a WiFi access point, you should be able to figure out where you're at by doing a search of the establishment that you're at.