Posted this on the WH boards but I'll post it here as well for people who aren't familiar with the venue.
Most of you will be coming from the west, in which case you'll more than likely take either the Meadowbrook or Wantagh Parkway straight down to Jones Beach. It is normally a painless ride with no traffic. They'll be cabs and ubers available after the show for those of you who are not driving. It is not too bad getting out of the parking lot after the show as the police basically just let traffic flow freely from the parking lot onto the parkways. The area where the venue is is not very populated at night (outside of when a show is going on), so they can kind of just let the cars flow.
Cups for alcohol are required here. They'll give you a hard time without them. State park police (like SPAC) patrol the lot. As far as I know, there is no grilling. Check the weather in advance and note that they'll be almost a 10 degree temperature drop once you get near the water, plus the wind coming off the water also makes it feel colder.
The beach is easily accessible with a short walk. Note, the venue is in the bay, not the ocean (where the beach is), but like I said, the beach is very close. There is basically one enormous lot (and a second lot which is used when the first fills up, but the second never gets close to filled.
Here is the lot you want to be in:
https://www.google.com/maps/dir//40....3.50907,16.25z
Also, as you can see on the map, the real beach is south of ocean parkway (there is a tunnel that takes you under ocean parkway that is accessible from the lot. The theater sits in Zack's bay. They'll be toll booths as you approach the venue, don't pay as concert parking is free. The tolls are for people using different parking lots for beach access.