Thanks for the advice all. Heres some info from the sccgov site with a link for anyone else thats interested:

Annual Passes
* Annual Venture Passes can be purchased for both vehicle and vessel.
* Annual Vehicle Passes cover all vehicle entrance fees at all Santa Clara County Parks, excluding Sunnyvale Baylands Park.
* Annual Vessel Passes cover all entry fees for power and non-power boating vessels at all Santa Clara County Parks which allow boating.
* Annual Passes are valid for one year from date of purchase.
* Annual Passes for vehicles are $65 and Annual passes for vessels are $65 each.

http://www.sccgov.org/portal/site/parks/menuitem.efb16479ca7a0488dfe093102830a429/?contentId=bc7498ba77784010VgnVCM10000048dc4a92____