I know that some people use two GPS units at once. Do you use one GPS to show a calculated route and another to show a large-area overview? Two calculated routes? I think that a large overview would allow me to occasionally ignore the route calculated by Garmin for a while. (For example, to see a freeway bypass of a small city when my GPS is set to avoid freeways. Stopping to allow freeways would not route me to the backroad on the far side of town.) So, who uses two GPSs and how?