T-Al,
On a trip from SoCal to St Louis in 2001, my buddy and I took this route:
Vegas (just a few hours)
Zion (1 day)
Escalate (1 day)
Bryce (1 day)
Capitol Reef/Canyonlands (1 day)
Arches (0.5 day)
Mesa Verde CO (1 day)
Silverton, CO / Durango / Pueblo (1.5 days, stopping various places)
Kansas (1 day, mostly driving)
Missouri (1 day)
I second Southern Utah. Some amazing territory, I wish we had spent more time in Escalante in the Grand Staircase. I have since been to Zion twice after this trip and loved it. It's is tied with Yosemite as my second favorite NP (Yellowstone being first). The other parks in Utah are nice, but don't hold a candle to Zion IMHO. Mesa Verde is really interesting and definitely one of the most unique NPs.
Also, I've been to the Redwoods and Sequioas. *I* think they are quite different, but that might be just me. If you've never seen them before, the size of the trees will astound you. Also, of the 5 plus times I've been to the Sequoias, I've always seen at least 1 bear.
For a frame of reference, my buddy and I both love the outdoors, hiking and seeing wildlife.
If you decide to do more than a couple of NPs, it might be worthwhile to get a NP Park Pass, or an incredible deal if you've over 62 (?), you can get a senior lifetime pass for $10.