So to make myself feel better I did ride up Mt Diablo on my bike. I stopped short of the summit just because Mark and Jan wanted to take me out for my birthday, but I easily could have made it and I think this next Saturday, I'll do it again and give myself more time.
I think the thing with biking is that you can easily compensate for muscle weakness. Others on bikes certainly did pass me and it was partially because I was on a mountain bike, partially because I have lower gears available to me, and partially because I was just going slower.
Once again I was way exhausted to the point the Jan was worried about me at dinner, but I recovered after a fair bit of sleep.
And the ride down. Pure speedy bliss. Make me wonder why I ever descend on foot at all. Took 30 minutes tops, and it was fun to chase the cars down. I think for Shasta I really should work on skiing. What I love about biking up (and I would guess skiing too) is that the climbing adage of the summit is only half way, really doesn't apply. You can pretty much kill yourself going up and just have to save enough energy to descend safely. I like that.