I set a really silly goal when I first started riding about 2 1/2 years ago to ride for 3 hours and best 20mph. Went out at 6:30 am to beat the heat and rode about a 3hr loop and got it at 20.2 mph. GPS/Strava had it at 3800 ft for 60mi, but that's a lie. It has to be only maybe 2800 to 3000 ft for the 60mi. Nowhere close to 4k.
I was surprised at how little power on even just a road bike it took to do it. AP was only like 185 and NP like 200. I almost wonder if the meter is reading correctly to go over 20mph over 50ft per mile. Not that hilly, just seems low.
But, actually bothered to force myself to eat and drink on a time schedule and that seemed to help my energy really well.