What kind of spring are you talking about? Early? Late?
March is perfect for Death Valley and the Mojave National Preserve.
Fly into Vegas on Southwest real cheap.
April - southern Utah - Zion and Grand Staircase - not the high country.
Again Vegas and maybe shuttle into St. George.

If you want to go east - spring is the perfect time to ride the Natchez Trace Parkway.
Very different than Colorado.