Well, you live in Palo Alto so you have several great climbs to train on - OLH, Kings Mountain, 84, Page Mill and Highway 9. I suspect the bottom portion of Kings or 84 will match the climb at the Games. I liked the first 10 minutes on Kings starting from Tripp to the Park and then coast down and do it again. I like the climb up 84 since it was not that steep and it was easier to keep a higher cadence and more speed. OLH is very picturesque and fun but at times too steep and the descent not great. Hence ride up OLH and down 84 and repeat - hard workout. Off days, I suggest an easy spin 20 minutes (under 100 watts). You can tack on an easy spin after the repeats as well.
Good luck with the HC.