Google Maps exists for PalmOS, and it works Just Fine in GVM. It happily downloads maps as well as traffic information and POIs (in areas where this is available).

I'm not going to try to install TomTom or something similar on the GVM, I'm pretty certain it won't work, it's pure ARM code for one thing (Google Maps is m68k).

The current version of GVM can't see the BlueTooth interface of the N800 directly (only indirectly, as when you go on the net through a BT/phone connection with your Nokia tablet).