And I was one of the ones who mentioned SD zoo. If I can ever get stationed in San Diego I'll join as a member even if kids are grown and gone. The tropical fauna is as impressive as the animals.
Do you have the option of another trip next year? I keep saying Jax but I haven't doubled checked, you could get to CA in four days of full driving: 1. Gulf Shores 2. West of HOU 3. NM/AZ 4. SD.
Then, take three weeks in CA:
San Diego: Zoo, La Jolla, Gaslamp District
LA: La Brea Tar Pits, Ronald Reagan Presidential Library, Drive Pacific Coast Hwy through Malibu
(we've stayed at a campground in Pasadena near Disneyland.)
Morro Bay/Cambria with Pacific Coast Highway in Toad.
(I think you could take 101 between LA and Morro Bay in RV but defer to locals on that.
Sequoia/Kings Canyon (although Mariposa Grove in Yosemite is a good way to see Sequoias in a time crunch),
Camp east of SF and take one day in city
Yosemite,
Finish up with a day at Lake Tahoe and come home on East side of Sierras or cross Tioga Pass but again I defer if Tioga Pass is doable in an RV and Toad. I've only driven that twice and it was in a truck not towing.)