RV roadtrip

Why are you going to Park City? Days 9 and 11: Park City, Moab, Tulluride, Aspen -- you are only going to view these places out your window. Why so much time in Aspen? These little kids will need to get out of the vehicles and blow off some steam. So many thing TO DO in these areas. Instead of just driving through them, you should stop and enjoy. Six huge motorhomes traveling together is a problem, when you're coming into a small town and want to stop and look around a rock shop, get an ice cream cone, drop in a museum. E.g., the kids would love the fish fossil quarry outside Kemmerer; the museum at Fossil Butte a short distance away. A 1/2 day rafting trip out of Green River or Vernal; Dinosaur Natl Mon. Thermopolis would be a hoot for kids - hotsprings playgrounds. You're skipping Glenwood Springs? Personally, it doesn't sound like fun to me.

Too much Aspen, waaay too much Cheyenne, not enough Yellowstone or Moab.

And I second Dinosaur NM.

They're in Cheyenne for several days of the Frontier Days hootenanny I assume ... but I agree that Yellowstone NP deserves two nights more, and Aspen less. Nothing wrong with Park City, as an alternative to SLC. Stay at elevation as much as you can!

Can we assume that you have either previously visited - or are not interested in - the national parks of Utah, plus the Grand Canyon?

Wow, that's some kind of caravan of RV's..........Slow it down dude. Traveling in an RV will be slow.
With a total of 6 RV's can't imagine how much your average speed will be, probably figure around 50-55 mph, if that. Heck it will take you guys an hour alone just to refuel, each time.
Hope you have a full day in Denver for your RV run through and shopping, probably require a night.

Most likely you'll be happier if you cook main meals outside the RV, get a BBQ pit and grill meat.

Do you require hookups, power-sewer-water, when you camp, RV parks?????????

Too much time in Cheyenne and not near enough in Yellowstone. Consider dumping the place all together, you have so much else to see and explore.
You will see a rodeo in Cody, don't forget the very nice western Museums.
How much of the Beartooth Highway are you looking at driving, I wouldn't bother driving any of it in an RV, especially something like a 34 footer. Dump it.
Chief Joseph will be more then scenic enough and add in Lamar Valley, you'll be very happy. Try to stay inside Yellowstone.
Dump Park City, out of the way, overpriced and overrated!
Why so much time in Aspen, why go at all. The place is sooo expensive
Too long of drive from Cheyenne to Cody in one day, especially in slow RV's. Cheyenne is a wasted stop, IMO, drive further towards Cody-Yellowstone.

Something a little different, maybe.
Day 1 Denver to Casper, about half way to Cody
Day 2 Cody
Day 3 Yellowstone
Day 4 Yellowstone
Day 5 Yellowstone
Day 6 Yellowstone
Day 7 Jackson, stay in Lizard Creek Campground or Gros Ventre Campground
Day 8 Dinosaur National Monument, nice drive and very underrated park.
Day 9 Moab, it will be hot, dry hot. Do your activities in the morning. Could spend a half day playing in the Colorado River, should be fine for the kids.
Day 10 Moab
Day 11 Telluride , might try the towns campground. https://www.telluride-co.gov/181/Campground
Day 12 Black Canyon of the Gunnison, stay in the park.

Day 13 Glenwood Springs
Day 14 Glenwood Springs - Denver

But Joe - the trip is based around the visit to the Cheyenne Frontier Days ... that's what is pretty clear. But they are skimping on Yellowstone NP as a result of that.

I agree that a caravan of six large RVs will be slow - I think an average of 50 mph is ambitious over the long haul.

I also found some of the selections unusual, and the time in each a bit odd, but (a) with such a big group it probably means the itinerary was designed by committee, and (b) presumably the OP has checked out the RV campgrounds they are booking, and found them suitable, with things for kids hopefully.

I think it's a bit early to be too critical - when we don't actually know the RV parks in places like Aspen and Park City.

Day 1 Denver - Cheyenne (for the opening of the Frontier Days)

Without actually knowing at all, I assumed they live in Denver and all own their RVs. If they are all flying to Denver and renting the RVs, then it truly is a major expedition.

His/Her profile shows Brazil, guessing they are renting?
This is based on them not knowing the country at all, didn't mean to be critical.
Just hate to see anyone spend time in Cheyenne, let alone 4 days, kill me now master! Plus it's only 2 hours from Denver and with that route they need to cover some ground, just want them to see some cool places, can't really experience Yellowstone in 1 full day but that's me..

Ok, thanks for all the inputs, Im already changing some stuff on our trip, lets go by parts.. 1. yes we’ve been to the US several times, although Im brazilian my kids are
proud Californians 2. we really enjoy rodeos, thats why spend 2 full days in Cheyenne, however for me, personally, is a bit too much. 3. 99% os the places we are staying are kids VERY friendly, and I am stull really open to new suggestions 4. I agree Aspen is over priced and not the best place, thats why my family will just spend a night there... been there done that, but im planning for other families as well so i wrote the plans for the majority... 5. about Park City we are staying at Heber City, in a Rv resort... 6. Glennwood Springs been there on summer and winter, very very nice!!! We are used to drive long distances... around 600miles a day and the kids are used to these as well... all our plans are mutable, this is the first sketch and I really appreciate all the inputs you guys gave me... so keep them coming!!!! Namastê

So are you renting these six RVs in Denver?

Yes, and spending some days there, prior to our trip, to explore Denver and surrounding areas.