Gregg, I use a Garmin GPSMAP 276c. In most cases you do not download "MAPs" from Funtreks (as far as i know) or other books websites, you download
routes, tracks or
waypoints (routes and tracks contain a collection of waypoints). The maps usually come from the GPS vendor (in my case GARMIN). There are some free maps available for Garmin devices but I do not use them at this time and they dont come from the book venders.
This is how I setup my GPS. I add all the maps from the Garmin TOPO series CDs into Garmin Mapsource which runs on your PC. I then add or create way points and routes (I only use tracks for recording where I have traveled) into Garmin Mapsource. Mapsource also lets you modify existing way points and routes.
Once I have all the way points and routes setup to my liking in Mapsource, I download them into my GPS. Since my GPS is limited on memory - I only can only download the maps in the area I am traveling so I sometimes carry a laptop to make changes if i am out longer than a weekend.
I usually print my own maps using the Garmin Mapsouce program or maps downloaded from the USGS service which are free.
Since you are in the four corners area I would recommend purchasing some maps from the
Latitude 40 map company as they are some of the best maps I have ever used for off roading.
Hope this helps
P.S. I wanted to add that the above should work for most Garmin GPSs. Also when purchasing a new GPS some of the features I look for are how much memory does the device have and how many way points ,routes and tracks can the device hold. To my knowledge none of the newer Garmin GPSs can hold the same amount of way points and routes as the GPSMAP 276c.