We are also from San Diego and will be making the trip for the 4th time. I think the kids enjoy it more than I do. They really do put on a great program for kids and have some exciting things planned this year to take it to another level. Hope to see you there.
I must have been inspried by this thread in the past and created a similar tarp system that clips on the buckles of my Softtopper top. I used this Aluminized nylon which seems to have some pretty decent heat rejection: