How much time are you planning to spend visiting the parks in Utah?
Do you have any camping reservations at the Parks?
Do you dry camp or prefer hook-ups?
Some of the National Parks have turned into quite a zoo this year due to folks doing road trips and trying to vacation without flying and doing hotels etc.
Besides the "Mighty Five"
https://www.visitutah.com/places-to-.../the-mighty-5/ You can also sneak down to Grand Canyon and Monument Valley or up to Grand Teton and Yellowstone.
We'd be happy to help with some alternative camping ideas in State Parks close to National Parks. Often times it's easier to set a base camp and travel to the parks in your truck.
If you are interested in indigenous peoples history and ruins this is really the place for some very unique and interesting hikes.
Plenty of fuel stops along 93. You'll intersect I-15 and head up the Virgin River Gorge to St George. From there its a about an hour to Zion. I'd recommend Zion Canyon campground in Springdale. It's literally at the park entrance.
From Sprigdale you can use Hwy 9 to 89 then north on 89 to Hwy 12 and Bryce Canyon. Ruby's Inn is the best full service camping option just outside the park.
From Bryce you can take HWY 12 to Capitol Reef NP. Wonderland RV Park is a really nice and full service just outside the Park. Great camping inside the park at Fruita Campground if you can get a reservation. Hwy 24 from Capitol Reef will take you to I-70. Go east on 70 to Hwy 191 and Moab. I don't have any particular recommendations in Moab as I usually dry camp in the area. Moab makes a good place to stay and visit Arches NP, Canyon Lands NP and Dead Horse Point State Park.
Let me know if you'd like other options based on your camping preferences.