Personally, I prefer to stay off of the state and federal highways. One of my reasons to tour is to enjoy some solitude, observe the scenery and wildlife, and absorb the local culture. You definitely need to do some research if you plan on using back roads. You also need to be prepared to improvise. I probably overplan to some degree, buying several different maps of the area I plan on travelling through if available. I have no desire to spend day after day riding on a state highway watching the cars go by. I also have no deisre to pedal most of the established routes designed by others. Their idea of interesting places may be vastly different than my own. Make sure you are not on private roads, be prepared for the possibility of going a day or two without the ability to re-supply on some of the items you may want, and know that you may be peddaling on some roads that aren't bike friendly. (Dirt, rocks, mud, etc.) Most of all, ride the type of route that appeals to you, and have fun!