In addition to the GPS, I often refer to the Atlas/Gazetteer for whatever state Iím in. As often as I pull one of these things out, I figure there may be others that do the same. I found a company that makes a storage sleeve that protects and keeps the Atlases organized. Blue Ridge Overland Gear makes some great products to protect your gear.
Check out their website: http://www.blueridgeoverlandgear.com/
With optional velcro bag for pens, etc....