Did my first 100 miles (~1600m climb overall) early last year, and like most of my cycling - by myself. Glad I did it but it was horrendous at times; it was cold and windy, I sat by the side of the road on the biggest single climb rocking trying to spur myself on, think I got a puncture early on and never tried it again. Good crack overall though - just wish I had gone with a buddy.
Good luck and sounds like you have a good plan .
Good luck and sounds like you have a good plan .