Last month my wife and I took a mountain biking vacation in the Lake Tahoe area and, of course, we took our GPS receivers along for the ride! While I posted a trip report, complete with GPS tracklogs, I haven't quite fessed up to one thing.
You see, I took my laptop along for managing waypoints, tracks and maps, but forgot to take my Garmin U.S. TOPO CD. I was incredibly disappointed, since my wife and I were both sporting handlebar GPS mounts so we could keep an eye on our progress and to help us keep on track. But I'm posting today to keep you from suffering a similar fate. And if nothing else, the method described below keeps you from having to load the CD every time you want to put a new topo map on your GPS.
Putting Garmin TOPO maps on your hard drive is incredibly simple, and it has to do with the installation. Create a folder on your hard drive and copy the contents of the CD's to it, including the setup disc. Then navigate to that folder and run setup from your hard drive, and not the CD. That's it!
If you've already got a Garmin MapSource program (like City Select) on your computer, it gets a little more complicated. You could uninstall and do the above, or check out this thread on geocaching.com's discussion board for an alternative method that involves a slight registry hack.