Probably the best software for outdoors and not street driving is the Maptech products
http://www.maptech.com/products/pock...ator/index.cfm
Pocket Navigator
Pocket Navigator software displays Maptech Terrain Navigator topo maps, Maptech digital marine charts and AeroPack charts (each sold separately) on Pocket PC computers. Connect a GPS receiver, and you'll see your position right on the screen. It's the most portable solution for taking Maptech outdoors.