5) I like the woops and those little jumps past the 14 mile bailout (that is a fast little section)
Those are a lot of fun if you're hauling ass.
On the mountain bike my favorite is Blue from 1 to 14.
My usual Croom ride is Parking #1, blue ccw, sugar mt loop, more blue, red connector, yellow ccw, skip the bypass, yellow on to parking 3, refill water, yellow ccw, red connector, blue back to parking #1 (maybe all of south blue if I'm feeling it but in the summer it's usually cut short and follow the blue north of the road back using the green connector).
In the summer that can be a real challenge though. In the summer I'll usually drop a lunchbox with a gallon of cold water and some granola bars in the bushes at the 14mi bailout before driving back to to parking 1.
On my cyclocross bike my favorite is the NW section of yellow. It rolls so fast and almost all the corners have enough of a groove to hook a wheel in and rail it even if it's sandy.