My Garmin Dakota with the handlebar mount is the only thing I use now. Day rides in France, long trips, it is worth finding or making a tracklog, then you can just ride without messing with maps or trail markers.
The topofusion track I loaded for last summer's Colorado -New Mexico ride was spot on, and much more detailed than the Adventure cycling track.
Jefe: To paraphrase Driving Miss Daisy "I've taught some of the stupidest people to use tracklogs" Actually they were all pretty smart, and I'm sure you are too. They all learned the basics of Mapsource and Google earth quickly, and it is time well spent.
FREE topo maps for the entire route can be found at:
http://www.gpsfiledepot.com/Along with some good tutorials.