When you turn off of the main road, there will be a driveway that goes up and to the right. At the top you will park on the gravel.
Yes, there will be an open bar with cider, seltzers, and beer, as well as non alcoholic drinks.
We're not exceptionally picky, though we may be a little disappointed if you show up in cut offs and flip flops.... or a white dress. Semi-formal or casual is fine.