Garden City Harvest hosts this type of thing in two different ways: one at a price (slightly more affordable...) of $100 where we host a chef at one of our farms, our local vineyard, 10 Spoon, offers wine, and guests eat out in the fields. It is a magical event, and made with local lamb, veggies, and talent, plus it's organized by a local group.
We also host a farm party at the same farm, for a more affordable price of $15 that includes a farm fresh meal and a local band. It ends up being a much larger affair...Another idea we have come up with is hosting a farm meal in the mid to late winter, where we cook with all local food - which seems an impossiblity to many - it's the middle of a Montana winter, where nothing is growing. Our chef, who is also one of our farmers, cooks up food he has put up for the winter into a simple, family style meal. We're doing it at a local hall this March 21st, and only charging $15.