Don't know all the details of your schedule, but you may want to consider the following itinerary after leaving Colorado: Visit Canyonlands NP and Arches NP near Moab, UT. Easy access from I-70. Recommend Shady Acres RV Park in Green River, UT, just off I-70 and away from the busy bustle of Moab. Easy drive from there on mostly scenic back roads to Capitol Reef NP, Bryce Canyon, Zion, Cedar Breaks and then on to Las Vegas via I-to/I-15. While in Las Vegas area, try to see Red Rock Canyon NM close by, and the State Park featuring the former vacation home of Howard Hughes just a few miles away. From Vegas, I would go to Death Valley through Pahrump. Stay a night there if you can. Several really nice RV Parks. Just west of Death Valley, we have stayed in Lone Pine at Boulder Creek. Lots to see and do there: Alabama Hills where hundreds of Westerns were filmed; Manzanar WWII Internment Campo; Lone Pine movie Museum, and lots of great places to eat. Drive north in US 395 to Mammoth Lakes, which is fantastic in the summer. Ride the gondola to the top of the mountain, take the tram to Devil's Postpile and Rainbow Falls. North of Mammoth, head across Tioga Summit on route 120 into Yosemite. Doubt you'll be able to get a campsite in the Valley, but we've stayed at High Sierra RV Park in Oakhurst near the South entrance on Rte 41. Continue south to Sequoia NP. Then head for the Coast.
On your return trip, I would consider going a southerly route on I-40 to Williams, AZ and the Grand Canyon. Then see Meteor Crater just E. of Flagstaff. Get you photos taken in Winslow, AZ, next to the Eagles' famous "Flat Bed Ford". Gallup, NM has a lot to offer. Try to get to Santa Fe, NM and taste the food at the Plaza Cafe right on the town square. Order your enchiladas "Christmas Style".
Whew!! I hope you're younger than I. I'm getting tired just thinking about your trip. Enjoy!!