A few thoughts on routes etc.: -
I reckon the gentlest (
) way up to the Stones is from Sutton-under-Brailes, across the Stour at Traitor's Ford (which is a real ford, though usually shallow, but without a footbridge IIRC). I haven't tried the direct route to the hilltop up Traitor's Ford Lane, but the indirect roads towards Hook Norton & then SW to the top are not too bad.
The climb from Whichford goes up a lot and tests the lungs. IME it's not a killer on a 67" fixed, but it would be a pity to miss the Norman Knight in Whichford before tackling the hill.
The direct climb up from Long Compton is pretty brutal, despite the lack of chevrons. I used the 24" gear on the way to Chipping Norton. I haven't tried the A3400, which looks gentler & might be a plausible option if motor traffic were to be both light & driven intelligently...
Banbury has breakfast options. Our CTC group has used a good (chinese run) cafe, but it opens at 9 a.m. There are a couple of Wetherspoons pubs that are open from 8 a.m. for breakfast.
I have no idea whether I'll be joining the ride. We seem to be having an annus horribilis. If things go well & we have another grandchild by then, it's still not clear which of the current health problems will still need support.
I seem to have posted this before completion. There is duplication., but it's a bit too late to delete the incomplete post.