Those are perfect things to bring, especially the giant umbrella.
In fact, I'll probably attempt to sit under it, so beware =P
You'll find yourself wandering around and gawking at all the other cars there for a while(yes, we must pay attention to the non-pintos), but otherwise its fun to sit around with other club members in folding chairs and share stories. Plus, its always interesting to hear the comments people make about the cars, and more often than not, you'll spend 10+ minutes with one person because they'll have a pinto story of their own to tell you.