Grab state maps, or a Rand McNally US Atlas, for a general lay of the land.
Supplement with state DOT bike maps, if available.
Use www.bikeroutetoaster.com and play with the various displays, see what happens when you ask for bike routes versus car routes, look at the profiles, etc. (like bikely.com but a bit cooler)
If you have GPS, upload the route to your GPS.
If you like a cue sheet, print one out from it, or save/e-mail a pdf copy to yourself and check it with an internet cellphone from time to time, or take (legible) pictures of pieces of it with your digital camera, and view it on the screen from time to time.
And, like others have said, ask here. Put together a route you think might work, describe it or post a link, ask for comments and stand back. Sift the replies and work from there.

This thread is the epitome of how a search can answer all of your questions. Thanks for all the valuable information.

See you in Garden City, KS and Rapid City, SD this summer :-D

Hi,

look to a detailed map. Search for winding roads - that's perfect for cycling. If there are no winding roads search for the minor roads.

By the way. I don't take care about traffic. If I have to make distance I also take the "Express Way".

For some of us, planning the route - as well as the other minutiae- is a part of the fun. It's a way to enjoy the tour process while still ensnared in our day to day work.

I find that more planning essentially means you'll make faster time to your destination, with fewer surprises (both unpleasant and pleasant). If your tour is not really constrained by time, you have more freedom to explore the meandering route, make mistakes, backtrack, et cetera.

So far, my longer rides have been restricted by time, as will my next one, simply because that's the way I've laid them out. For them, I'm looking at routes, maps, traffic volume, and getting as much local input as I can find to be able to see what I want to see within the time off work I've set aside for the ride.

I think I'll plan my long tour next year with a much lower miles-per-day requirement and see if I like that better.