I regret not taking the final "scenic" detour. I anticipated a bigger detour than it actually is (just an extra 200 metres distance and 30m of climbing, so not really worth worrying about considering what went before).
My main achievement was not walking any of it. I was very apprehensive about it beforehand but I managed to grind my way up all the climbs.
I overtook some people and some people overtook me. Bodyweight is clearly the issue for me, not gears.
Some lower, "touring", gears would have been nice but I stuck to my 1rpm, "sorry to do this to you knees", approach.
On the penultimate Dartmeet climb I did wonder if my knees would ever forgive me as I saw the climb stretch out above me, with the sight of cyclists winching, and walking, their way up it.
We caught up with some 8am starters about 3/4 of the way round (I assume they were anyway). Some were going desperately slowly by that time and I expect there were internal questions being asked ("What the f*** was I thinking?" perhaps). I'm sure they'd be thinking it when they got to Dartmeet and Widdecombe on the Moor anyway.
This ride convinces me that Disc Brakes are the future*. I've no idea if I'd have been able to stop in the wet, it was as big a workout for my forearms as my thighs even in the dry.
*Unfortunately my disc-braked "Genesis Day One" is a Single-Speed and my heart would have exploded within 300 yards of the start.