The trail between Timp and Baldy could be amazing, with a little TLC. Same with parts of the singletrack that parallels Timpooneke road.
Based on the map, I think it would be possible to ride from Bountiful, via Skyline, etc, to Evanston, WY, through the Uinta's, to Strawberry Res., and on into Provo Canyon, finishing in Orem, or other points north. That route would be 99% dirt road, and really long.
I think it'd be possible to do a Payson to Layton tour.
Take a look at www.skidmap.com
, brilliant resource!