A fellow Threeper in Wyoming sent me this tutorial that shows you how:
|Go to http://store.usgs.gov/|
|Find your AO|
|Mark what maps you want to download and click 'view download cart'|
|Click download. File will download as a zip file and each map will save as a .PDF|
|Change printer settings to "Tile" in order to print a full sized map.|
And there you have it. If you are so inclined, you may take your maps to Kinko's or somewhere that offers laminating services to protect your maps from moisture. These will easily fit in your backpack and don't weigh much of anything.
If nothing else, you should download maps of your AO for future reference. You never know when you'll need them.