I use a GPS and http://www.openstreetmap.org/ , along with google.

But if you're married to paper, I would recommend the following:

- Map your route using google as best you can.
- Supplement it with openstreetmap above - for street density, conveniences, trails are mapped, etc.
- use print screen to copy and paste images of your route to photoshop, or another image editor.
- get a profile for the route from here.
- note conveniences and special features on your map, as well as scale.
- cut the map up into the proper chunks following your route - so it looks like a bunch of little handlebar bag maps like this.
- buy a state map for each state you tour through, and keep it packed somewhere for when you get lost.
- If you're feeling really fancy, get your maps laminated.