Sounds like fun, kudos for your work-around creativity! So you feel sprint bike is equal to effort of sprint run? We should ask Buckley about that, as you may know he was a semi-pro bike racer before his re-incarnation as a stellar endurance runner.
judging by my breathing effort, and "perceived exertion", I was breathing about as hard at the end of the 1.75 laps as I would at 200m running . Penrose is roughly 1/5 miles so 1.75 laps. . . equals about . . . 1/5 miles = .2 miles plus .75 times 1/5 = .15 miles . . . total .35 miles or . . . 563 meters (per metric conversion calculator). but with zero injury, not even a twinge.