Need help finding a certain location

Hi guys, Today when I turned on GTA V I spawned into story mode as Trevor and was in some sort of outdoor gym with beefcakes in banana hammocks. Now, I was away from my xbox because I expected to spawn in and be idle for a bit but when I got back it was just in time to see one of the beefcakes finish beating me to death for no reason, as I was just standing there. Can someone direct me to the location of this place so that I can go kill everyone there please? Thank you.