Hmm....
I just fool around on the stability ball about 3 times a week.
Crunches of multiple orientations and push-ups.
Shoulder lifts/Bicep curls @ 10lbs
Calf raises with light weight.
TONS of lunges - standing, lifting, kickback lunges, double leg lunge... with light weight as well.

Your endurance should come on the bike shouldn't it? I mean there's no point using up an hour @ the gym when a good aerobic ride is available. And for sprinting, I guess heavy lunges should build that power... so I think your train is on the right track

I dunno, I don't know much about jimming... I just work on my muscles that I know I need on my bike.

Good luck,
-Peter