Escalante area is likely best known for its stunning backpacking opportunities. There are also plenty of hiking and canyoneering adventures. This makes a great spring and fall destination and would take a lifetime to fully explore.
The Red Desert, in south/central Wyoming, is touted as being one of the largest unfenced areas in the lower 48. Visiting the Red Desert is like stepping back in time. Huge views unspoiled by building and structures, wild horses, and very few other visitors.
The Roost is a very remote area of south eastern Utah. Canyoneering adventures in Robbers Roost tend to be fairly dry, and have long exits. The area was used in the late 1800's and early 1900's by outlaws, hence the name.
The Wasatch Front offers excellent hiking, climbing, mountain biking, and skiing all within a short drive of Utah's major population centers. There are many peaks to hike, climbs to climb, and routes to ski.
Quite possibly the canyoneering capital in the US, Zion offers canyoneering, climbing, and hiking among towering sandstone walls. The park itself is a destination, but within a short distance of the park are many additional wonders to be visited.