Senior Week advice for College Undergrad

I am a senior in college and will be graduating in a couple months. I’m planning senior week for my class and I have a beach Trip on the itinerary. It’s will take us 2 hours at most to get to the beach. How many hours should plan to stay at the beach for about 70 college 20 somethings. I don’t go to the beach often so I don’t know what is reasonable.......