I just did a 19 mile loop with about 2000' of climbing and I am beat. I was on the granny gear at the steepest, longest part and was down to 5 mph. I thought I was ready for Diablo but after today, I think I'll do the 19 mile loop a few more times. Then, I'll climb Cummings Skyway from Hwy 80 a few times. When I can do that out of my granny gear, I think I'll be ready for Devil's Mountain.
How much training did you do before climbing it?