I think I have an itinerary! I ended up taking Seattle and all of Washington out of the trip in the interests of less backtracking and having more time in the places DD is most excited to see. Eliminating the couple of places we wanted to see in WA let me cut down most of the longest driving days, so I don't think I have much more than 8 hours of drive time on our worst days with most being shorter and/or broken up by several stops.
Day 1: just driving, Michigan to Wisconsin
Day 2: House on the Rock, WI. Driving on to Minn.
Day 3: A couple of Little House on the Prairie sites DDs both want to see. Corn Palace. Drive on to Black Hills, SD.
Day 4: Badlands NP. Wall Drug.
Day 5: Mount Rushmore. Jewel Cave.
Day 6: Devil's Tower. Heart Mountain Interpretive Center. Cody Rodeo. Stay overnight in Cody.
Day 7: Yellowstone. Drive on to West Yellowstone.
Day 8: Yellowstone.
Day 9: Yellowstone. Drive up into Montana via north entrance.
Day 10: Glacier NP.
Day 11: ??? with my uncle in Montana.
Day 12: Drive down to Twin Falls, ID.
Day 13: Craters of the Moon NP. Drive to Salt Lake City.
Day 14: Capitol Reef NP.
Day 15: Bryce & Zion NP.
Day 16: Grand Canyon NP. Seligman. Stop somewhere in California.
Day 17: Joshua Tree NP. Drive to Anaheim.
Day 18, 19, 20:
Disneyland
Day 21: Universal Hollywood, Griffith Park. Drive as far as San Luis Obispo.
Day 22: Big Sur. Pfeiffer Beach. Stay in Monterey.
Day 23: Monterey Aquarium. Santa Cruz Pier.
Day 24: Lassen NP.
Day 25: Crater Lake NP. Grants Pass, OR.
Day 26: Drive down the coast. Stop near Mendocino.
Day 27: Arrive in San Francisco, the day before move-in. Walt Disney Family Museum. Dinner somewhere wonderful.
Day 28, 29, 30: Move-in and family orientation.
I'm pretty happy with the way this looks, but I would appreciate feedback.