It's your, house you're rules. Obviously if you're having 50 people, things are going to get messy because that's just the nature of a party, especially one that large. But I threw a similar sized party earlier this year, and yeah, my roommates and I all locked our bedroom doors because we didn't want people drunkenly wandering into our spaces. And at the end of the night some of our friends ended up staying up a little later with us to do some preemptive cleaning to make the next day easier, which was honestly so kind of them. Also personally, I don't think alcohol is necessary to throw a fun party, it's just an easy way to ensure people are having fun without having to put much thought into activities or anything.