Jason,

I informed my contact early on that'd we'd come do a site visit and to confirm all the logistics. I already know the layout and where they want the cars but I have a laundry list of things I want to check in with them on.

Short list just as examples of items to check on:
Signage
Tables / chairs (they already said we could use some of theirs)
Bathrooms (they have bathrooms inside but they may have some portajohns as well -- or we may need some)
Audio / Music (we are going to set something up aren't we -- so we can use a mic for announcements) - If someone has a good system we can use I won't have to ask them
Access to power (shouldn't be an issue but just want to check)
Food / Water / Soda (Do we want to sell dogs / burgers? or other food?) - They do have food / drinks (cheese / meat boards etc in the wine tasting area and I don't want to infringe on their sales - so if we want to do something easy / simple let me know - for I'd want to respect this aspect of things for them)

There's more, but you get the idea. Do you want me to call and set up a time? I'll ask about weekend dates if available. When? May? June?

Let me know.