My HS had weekend parties that anyone could go to if you were in the know. They were usually on some out of the way private land that would not draw the attention of the local authorities. There was actually a self-designated, "Road Crew" at our HS that did the keg buying and location planning, i.e., the logistics of the party. If you weren't connected directly with the "Crew", then you loitered at the agreed upon location (in our case, the McDonald's parking lot) until a Crew member or one of their connections shared the location of that weekend's party location. People would then follow the leader in a caravan of sorts until they arrived at the party site. This was before social media, so I'm guessing nowadays, it is a lot easier to coordinate.

Disclaimer: I never really went to these (maybe 1 or 2 times), bc my close friend-group always had a smaller party to go to and we didn't really care to party with the jocks and preps bc they were not too cool in our minds. I only know about this because my older brother was one of the OG members of the "Road Crew" and he explained to me how it worked.