Congrats, 10 min miles are very respectable if you can extend that distance a little.

In the gym I run on a treadmill, the kind that allows you to incline or decline by a quick push button. I know it's not the same as running in the wild, but I've had my knee surgery and not looking to beat up knees and ankles any more. Luv it, a precursor to my workouts. I'll do 5ks as warm-up for spin class or core.

For me, running is a litmus test for my fitness. If I can run a 5K and feel fine, ready for another workout afterwards...then I'm a good place fitness wise. If I fall apart after 2 miles, come off feeling wiped...then I've got my diet, sleep, lack of routine exercise to blame.

As far as running as training for cycling, I would agree the cross over is limited to general cardio and good burst power for climbing. That said, I know of a few cyclists that are trading cycling time for running, the workout you get in 30 to 45 minutes is substantial, and you don't need a lot of prep, gear and fussing. And like cycling it leaves you clear headed, but it doesn't take 2-3 hours.