Zion/Bryce/Grand Canyon quick roadtrip

Curious what people's thoughts are on the following roadtrip:

April 17th (Fri) - fly from Boston to Salt Lake City, pick up rental car, drive south

April 18th (Sat) - Bryce National Park, stay in area

April 19th (Sun) - Zion National Park, stay in area

April 20th (Mon) - Drive to south rim grand canyon, stopping at horeshoe bend, stay in area

April 21st (Tues) - Driving to Phoenix for flight home

Too much in this time period? I feel like I'll never get the chance to be out this way again, so I'd like to try to see all 3. While I know Vegas and St George are closer, the prices are about $300 more for Vegas and double for St George.