I have a older Garmin Streetpilot 2610 (actually the BMW version - Navigator II) which I use in the car and on my bike. A very good unit which is also very robust.

Street mapping is very good but I'm now looking to put tracks and topo information on it for when the car is off the main roads.

Is anyone running any offroad maps on this particular unit? Can I run 2 sets of maps at the same time, eg City Navigator + off road maps?