Only have time for 3-4 National parks/attractions in Utah. Which do you recommend?

I'll be doing a 15 day road trip through Utah/Arizona/California this June, with 3 buddies of mine. We will be driving in my SUV and be camping majority of the time.

We really only have time so see/camp 3-4 of the National parks or main attractions in Utah.

From this list Utah attractions which would you recommend seeing?

Of course, if it is not on that list, please feel free to recommend!

Really, we are looking to visit the most scenic places in Utah and would like to hike some cool trails and camp in nice secluded spots.

Thank you!

EDIT** Here is my full Roadtrip Itinerary