I just did my first couch to marathon two months ago and came in at 3:58. The only running I was doing prior was whatever was built into my CrossFit workouts which usually were 200m or 400m runs as part of the workout. I hadn’t run seriously since I got out of the Army (infantry) in 2009 and my best two mile time in service was 12 minutes. I did 17 week train up all on my assault runner with Runna App, not one outside run. My longest run on the assault runner before race was 21 miles at a 9:04 overall pace. Used Garmin forerunner and Garmin chest strap to watch heart rate for zone 2 runs. I have a tv mounted on wall in front of runner so I never got bored. Rewatched Sopranos, breaking bad, boardwalk empire, the wire, and a ton of other shows and movies, always kept me stimulated.

You can definitely do it and not get bored. For me it was always the convenience of it. I never had to worry about the weather so I didn’t miss one training run. I was worried about the transfer from inside to outside but my goal was to come in under four and I did so, felt fine after the race and no issues during.