We did Arizona and Utah on our own and it was very easy to plan

. We went for spring break in early April a couple of years ago.
We flew in/out of Las Vegas as it was the closest larger airport. We arrived mid-morning and spent the day exploring. Our kids were curious about Vegas so we walked around, played in the arcade in NY NY, and caught a Cirque show. We are not Vegas fans but it was fine for the day we arrived.
Day 2: We had brunch at Honey Salt (highly rec - an awesome farm-to-table restaurant) and then drove to Cable Mountain Lodge near Zion NP. We LOVED Cable Mountain. There is an outfitter, restaurant, grocery store, pool, laundry, and amazing views of the mountains. We had a one bedroom suite with a kitchen as well.
Day 3: Explored Zion NP - really amazing!
Day 4: Day tripped to Bryce Canyon NP - also amazing! It is smaller and easy to navigate around, a perfect day trip.
Day 5: Drove from Zion to Page, AZ. We explored Glen Canyon Dam for a short bit and then went to our tour at Antelope Canyon. If you aren't familiar google it! Antelope Canyon is an incredible slot canyon on Navajo land. Loved it!
Day 6: Still in Page, AZ, we floated the Colorado River. It was a 3 hour, 15 mi float with the guide telling us about things along the way. We got to stop at a little "beach" and see some petroglyphs while having a picnic lunch. We also saw Horseshoe Bend from the river. And wild horses drinking! It was awesome.
Day 7: Left Page, AZ and stopped to see Horseshoe Bend - really a neat site! We then continued to the south rim of the Grand Canyon. We found the Grand Canyon to be incredible. After a couple of hours here (we also had a picnic lunch having gathered items from the store on site) we continued back to Las Vegas for our flight home the next day.