In case you don't already know about it, Adventure Cycling has maps for bike tours, as well as doing supported and paid-self-supported-group tours. Look at their "Utah Cliffs Loop", "Grand Canyon Connector" and "Western Express".
If you buy the maps, they have a lot of details about services, elevation profiles, camping. If you don't want to, you can download GPS files of their maps for free, which you can view in Google Earth.
I'm thinking about Utah too, for a possible spring tour. I've climbed quite a bit near Moab, the season is really short - spring is cold and can rain or snow and be very windy, we usually don't climb until mid-february and get some storms... March can be great, it can already be too hot in late April. Fall is the most settled, but I haven't spent enough time there to know exactly what the right timeframe is.
The area around Moab / Canyonlands is spectacular. Arches Nat'l park. Castle Valley, the LaSalles... South of Moab towards Monticellos, the Abajo Range...
I've been to Bryce and Zion w/o a bike, would totally go back there. Incredible scenery. Southwestern Utah is surprisingly high - I think the Adv.Cycl. routes take you over an 11,000 foot pass near St. George, so it's tricky figuring out when to go - too cold and too hot at the same time.
Good luck with your planning!