I redid it on
ridewithgps, which shows the grades (if you click on grade; then you can magnify parts of the ride by selecting them). According to mapmyride, it has 2 cat 3, 1 cat 4, and 7 cat 5 climbs. Worst grade is actually going over the notch on 116; gets up to 10%, but only briefly. (I might check to see if the climb is easier in the other direction.) Middlefield is a royal pain: 700' down just to go right back up. I checked out going River Road the whole way north (and catching Chesterfield later from rt 9), but it was worse.