I've spent a lot of time in those desert regions during both time periods. October/November is definitely my prefered period. Lots of fall color with fewer driving hazards when passing through the high country in intervening areas. Also much more comfortable camping if that's your intent. As long as your contemplating Escalante, I'd keep going north into Capitol Reef, Natural Bridges, Arches and Canyonlands. Four weeks is neither too long nor too short for the desert without the California coast. In fact, it's about the same time span I devote. I doubt it's too short, even including CA. While in the vicinity I would certainly add Yosemite. Oct/Nov may not have the high water there, but it certainly has fall colors and a lot fewer people than spring.
Thanks Hank. I've been to Yosemite for the past 3 years. In fact, I did a week long workshop at the Ansel Adams Center last summer (taught by Charlie Cramer). It was great. So I won't be going there. I want to concentrate on the other areas. How far is the drive from Zion to the places that you mentioned (Capitol Reef, Natural Bridges, Arches and Canyonlands)?
I have to say, that the best shots that I've seen of distant mountain ranges have snow in them. Otherwise, they seem like mountain photos that I've seen a million times.
What could I expect if I travel in January in these areas? Will there be snow? I know that I won't be able to make it up to the bristlecone pines in January.