I think this is Mark, right? Hopefully I answered some of your questions by email earlier today.
Pickup a cheap $12 card and then depending on where you live, there may be free maps you can load onto it. Check out this thread:
http://www.topofusion.com/forum/index.php?topic=3796.msg106782#newIf not, the Garmin Topo 2008 DVD is your best bet for US-wide coverage of topo maps.
Start riding, download your tracks and see what you learn. Then try drawing a new track, uploading it to the unit and following it out 'in the field.'
Let me know if you have any more questions.