Hop on an early flight to Las Vegas, when you arrive pick up your small SUV and hit the road. My recommendation is to stop to pick up some snacks and supplies for your road trip, maybe even some ingredients to pack a lunch for your hikes.
On your way to Utah, you'll stop at Valley of Fire State Park to get a taste for the red rocks. The wave is a sight not to be missed! After you have done some hiking, you'll continue driving to Springdale, Utah - home to Zion National Park. You'll check in to the Quality Inn for two nights and head out to dinner. Stop at the park to pick up a map to plan your route for the next day.
On Friday, you'll wake up early and enjoy a free breakfast at your hotel. Drive over to Zion as early as possible to secure a parking spot. Hop on the tram and it will take you to your desired hikes. My favorite hike in Zion is the Narrows, it's in water and there are places to rent water suits. If you are feeling extra brave, try out Angel's Landing. It's for experienced hikers but the views are breathtaking. Bring a packed lunch or grab something at the hotel on the grounds. Make sure you take the drive through the park to really be able to take it in from the top of the mountain peaks. In addition, you can see the window through the tunnel that they carved back in the day, very impressive. Zion is truly a spectacular sight to see. The Zion brewery is a next door and you can enjoy great brews and eats there after a long day.
On Saturday, you'll wake up early and set off to Bryce Canyon. Bryce has so many lookouts, I recommend driving all the way to the top and then stopping at each lookout on the way down. Pick a few hikes to do - the hoodoos are the best to hike through. The elevation is higher here so take note if you are prone to altitude sickness. Bryce Canyon will make you feel like you are on another planet, there is so much to see and do. Highly recommend bringing a lunch in to eat. You'll check in to the Best Western Plus for a one night stay.
On Sunday, you'll hit the road and stop in St. George, Utah for some leg stretching in Pioneer Park. There are some great short hikes and beautiful photo opportunities. Grab some lunch and drive to your last photo opp of the trip, seven magic mountains. A group of neon rocks in the desert, do it for the gram. You are 25 minutes from the Las Vegas Airport where you will drop off your rental car and then take a late flight home.