Fantastic report and photos.
I’ve been to Greg’s Hut once, when we did the Pennine Way back in 2006.
http://tomread.co.uk/dufton_to_garrigill.htm
BTW, I don’t think Wainwright devised the Pennine Way. He certainly did a book about it, and, also the “Pennine Journey” (which he did devise). The Pennine Way was first proposed by Tom Stephenson in 1935, but didn’t actually come into existence until 30 years later.
Your mission to reach all the G/LDs and Cumbrian G/NPs by human transport is stunning! I enjoy this sort of challenge too, but being only a walker and not a cyclist, my options are far more limited!
I have done both Shining Tor G/SP-004 and The Cloud G/SP-015 as day walks from home. Once I did a 71km circular route, walking from home, taking in my three local SOTAs - Shining Tor G/SP-004, Gun G/SP-013 and The Cloud G/SP-015.
This included two wild camps - one on G/SP-004 and one on G/SP-015. I am planning to do this again, but actually over a longer route, and with just one overnight stop - but in a hotel!