The name of the game is breathing today. The sit-ups will be the easiest to breathe through. The bike (done at a proper pace) should be a bit more challenging. Coming then to the pull-ups, the main thing is moving efficiently through them. Not so quick that you die out, but not so slow that you're standing there looking at the bar. Finishing with that wreck bag/odd-object, it's get it done and then back to the sit-ups. So breathe well and move efficiently. Nice and easy.