I'm doing all the writing because you're asking all the questions that the TE gals so patiently answered for me as they got me "larned" on Diablo.

Yes, this is the South Gate route and it has a few flat spots and more shade. It climbs to the same elevation but takes longer to do it. From the junction up, it's all the same. FYI, there is potable water and restrooms at the junction. If the visitors' center at the top is open, I think they have bottled water for sale but I don't know if there are any spigots (but then you're going right back down to the junction).

There is a big parking lot at the train museum. We tend to park closer to the museum than to Andronico's (is that the right name for the market?). http://www.museumsrv.org/directions.html We can then walk to eats type places and bike shops as desired.

Ah, my climbing goal -- peanuts compared to others. There's folks on bikejournal going for the vertical century, 1,000,000 ft. Yellow has probably done double that already, but then she gets about 50 ft everytime she rides her driveway.