Next May-June (2013) we plan on taking our family on a road trip from Missouri to the Grand Canyon and possibly even further. We'll have as much time as we want for this trip, though we'd like to keep it under three weeks. I'd prefer to just get up and go and not worry about making reservations anywhere since we don't know when we'll be stopping at each place. We've been to Oklahoma several times so we don't plan on stopping unless something catches our eye. I'd like information on other sites to see on the way to the Grand Canyon.
We have a lot of places on our list of things to see already, but I know the best places come from people who have already been there. So far we plan on stopping at (in no particular order): Cadillac Ranch, Four Corners Monument, Petrified Forest, Hoover Dam, Winslow, AZ, Rockhound State Park, Canyonlands National Park, Monument Valley, Natural Bridges Monument, Barringer Meteorite Crater, Sunset Crater, and Arches National Park.
We really enjoy History (I have to stop at every Historical marker I see on the road) and being outdoors. The kids will be 9 and 4 they like dinosaurs and in general anything that has to do with the outdoors. We plan to take a route through Utah, Colorado and Kansas on the way home so that we can experience as much as possible on this trip.
I know this trip is a long ways off, but it will be the longest road trip we've attempted and I don't want to get home and discover I was right by something spetacular and missed it. Any help is appreciated.