I'd like to suggest April on the theory that Spring should be further along, perhaps spring vegetation also further along, etc. Must it be the third week? Fine by me, but I note that Cary cannot make the third week. How about the fourth weekend, or the second weekend?
My other reason is that April would leave time to take a nice Feb or March backpack somewhere around the Bay Area -- perhaps try to choose a trip with good wildflowers. Rather than introduce noise into this thread, I'll start a separate thread for that. I presume we would be talking about more or less the same collection of people, though.
Ken -- you said "Henry Coe??? Ohhh no. Man that place can get hot and those trails are sooo up and down."
My answer is "Not with proper planning". Temperatures are pretty reasonable in the Spring, and you can remove a lot of the up-and-down by going in from the South entrances, such as Hunting Hollow. See a longer description in the other thread when I post it.
Which reminds me -- what sort of distance and total ascent per day does this group find reasonable? What sort of effort do you see the SEKI trip you mentioned taking, Ken?