Hi babbske,

It looks like you have a very exciting trip planned and Im happy so happy for you. Having been to each of the places on your itinerary, I would like to recommend a few adjustments. First, I would drive the entire loop and not fly from Las Vegas to San Francisco. The reason I say this is because you would need 2 one way car rentals, which would include very expensive drop off fees, and second, A flight in the middle of your trip would add even more to your cost. I would also make just a few adjustments to your itinerary. Here is what i would recommend:

1- Los Angeles( Disney or Universal )
2- San Diego( San Diego Zoo or Legoland )
3- San Diego( Sea World )
4- Phoenix( overnight )
5- Sedona( Pink Jeep Tours )
6- Sedona( exploring Sedona, or perhaps nearby Clarksdale for a ride on the Verde Canyon Railroad )
7- Grand Canyon National Park- South Rim( if your are staying near the rim, book accomodations months ahead )
8- Grand Canyon National Park- South Rim( you may also want to consider using the Grand Canyon Railway to the Rim )
9- Lake Powell( consider one of the many lake tours on this beautiful lake, maybe overnight at the Lake Powell Resort )
10- Kanab( great base for accomodations with close proximity to 3 National Parks- Visit Bryce Canyon 1st )
11- Kanab( Grand Canyon North Rim )
12- Kanab ( Zion National Park )
13- Las Vegas( overnight, sightseeing, Hoover Dam )
14- Mammoth Lakes( Overnight on way to Yosemite National Park, via Death Valley )
15- Yosemite National Park ( arrive at Yosemite Valley via Tioga Pass Rd )
16- San Francisco( overnight, sightseeing )
17- Coastal Route 1 to Monterey( via Santa Cruz boardwalk, overnight in Monterey )
18- San Simeon ( Hearst Castle )
19-Santa Barbara
20- Los Angeles

So as you can see, I eliminated Palm Springs and Monument Valley and replaced with San Diego and Lake Powell, with your child in mind. Hope this helps.