The trail that runs the length of the range is horse, moutain bike and motorcylce only. Most if it is not open to real vehilces. Most the roads that head up the canyons (North Willow, West Canyon, Davenport) don't go very far due to the wilderness areas, and the fact that it is a step range. Hickman goes further and is less maintained than South Willow, but still not a difficult drive. Can't remember if I ever post pics of it here or just on UOOC. Still need to explore Box Elder more than I have.
Very beautiful area, however.
Be carefull in the winter in the narrows area. Can ice up something fierce. Few years ago took a scout group up (in November) and ended up with the equipment trailer in the creek (happy to say I was not the one towing it).
Still need to hike to the lake and top of Deseret Peak.