Now there's a bar top, as well as braces and cupholders in the back. It's more stable than I thought it might be, as the tops are attached to the doors. The Volt/Aged acts as a weight to hold the tops down, and a keg inside is ballast for the whole thing.
It's (almost) ready for its big debut at The Shipyard tomorrow night for the Escape From Berkeley dinner & party. Jon and I will add a few touches Friday morning, then pack it for an afternoon delivery.
I'm sure we'll need to add or change a few things after we use it Friday night, but it's basically done.