That will be fine for the climb. Most of the climb is probably 5-7%, with two downhill sections, and a few short ramps once you enter the park which are close to 20%. If you have any opportunity, it sure helps to pre-ride the course, just to get a feel for it. You're on good road for at least 3/4s of the climb, then make a left turn into the park onto narrow paths with a steep climb, a down hill, right turn, and then (as I remember) two more steep ramps to the finish. No one (ok, maybe a couple of really strong cat1s) has much cadence on those ramps.