In my opinion, I think you might be packing too much in this trip. You have five days for the Utah Parks and Mesa Verde, minus your drive time. So you'd be doing just a drive-by in Utah, plus all the setting up and packing to leave.
1.5 days is not enough time to see both Bryce and Zion. And 1 day in the Arches/Canyonlands area same. Either of those deserves a full week. You can easily spend a full month in southern Utah and want to return to catch things you missed. By the way, all or most of the Utah national and state parks have very easy short hikes (along with the tough ones) that anyone can enjoy.
Hard to tell you what to eliminate because we're all different. But I'd either skip Vegas, or go up to Yellowstone after Vegas, and save the Four Corners area including Mesa Verde and Utah NPs for a second trip.
