I played with Basecamp last night. Made a route, then right clicked on it and the menu that popped up had the option to convert said route to a track. might be what you're after. Tracks are nice as the don't care what mapset, if any, is on the GPS, just follow the line on the screen.
If the track that is created from the route has too many track-points for the GPS to accept there is the option to filter it down to the number of acceptable points.
Not all who wonder are confused