The "road" between Bahia Pt and Ventura Cove is all parking along both sides. Ventura Cove is mainly a swimming area and have been told by lifeguards before that kayaks aren't allowed to launch there. But seeing as they probably won't be there @ 0700, it's up to you. The Ventura Cove lot is large enough to accommodate trailers, but you'd have to roll your kayak to the water. The best place to launch is Dana Landing like Andy said.
BTW. The grassy area where that's pinpointed is kinda small. Maybe think about using the large grassy area as HQ for bbq, raffle, etc... as it has more room to accommodate canopies, chairs, whatever.
Either way, it'll be a fun event. Good luck and see everyone tomorrow.