the drivers suck? They're far better than in most states, imo. Anyways, I don't know what mountain biking events are going on in the summity county area, but there are some good trails there, can't list any off the top of my head, but i mean you have like a grouping of ski resorts with a ton of trails, so you will have no problems finding something to do, obviously. I think bikeCOLORADO would know more about this area...
I suggest you stay in fruita/moab for most of your trip, personally i like the riding out there, well i live 15minutes from fruita so i'm kinda personal to that area. You're not riding the whole kokopelli in one day are you (i don't why you would, or how)? Anyways, there are TONS of great trails out in the bookcliffs in grand junction and fruita, there's this one trail outside of fruita called Joes Loop i think it is, it's pretty sweet, it has this one part where you go around these little curves really fast and the trick is not to use your brakes
Anyways, also in grand junction there's a trail area by the colorado monument which has some great stuff, that's where i usually go riding. In moab, well tons of trails, if you stay right off of potash next to the river and by all the climbing along that road there's poison spider trail and portal trail, for pics of it check my web page in my sig. Lots of sand, but lots of slickrock too.
Anyways, stop by over the edge bike shop in fruita and get their trail suggestions and they have trail maps in there you can buy and what not. Remember, it will be very hot/dry out there. Maybe i'll see you out there
Have a good trip