barn rules

The number of horses at my barn is about to increase by 150%, as a local lesson barn is moving 15 of their horses and ponies to my barn on the first of November to stay for the winter. I'm not exactly thrilled about this because I like how small and quiet my barn is. I also like that there are minimal kids. There are a few kids at my barn currently but they are pretty mature and reliable. My last barn was all adults, though some of them acted a lot like kids themselves. All of the boarders at my current barn are respectful of each others space, I know all of the horses and their quirks, and I don't have to battle for ring time or play dodge-em with four other horses in the ring.

I know I've been spoiled with all of that space, though, and I've accepted the fact that the circumstances will change dramatically very soon.

My barn owner and I were talking about barn rules. With so many new people moving in all at once, there is the potential for things to get very messy. My opinion is that we should post the barn rules in a very obvious spot and have a barn meeting within the first week of all of the new people being there to introduce everyone and make sure we're all on the same page. The thing is we don't even have official barn rules because we've been able to function just fine with everyone cleaning up after themselves, being respectful of each other, and making sure their horses are behaving themselves.

My main concerns are:

-possibly having to schedule ring time because there are going to be so many lessons that the lesson program could literally take over the barn and all of the space
-if there is a lesson going on (or two), are they going to allow me to ride in the indoor with them? this is New England and it's going to start snowing soon, so though we have an outdoor it may be under 3' of snow until March like it was last year.
-making sure people clean up after themselves. this is a HUGE issue for me. I hate when people pick their horses feet out and then just leave the dirt right in the middle of the aisle.
-ensuring that people are aware of what they can and can't use. I'm lucky that my tack, grain, and other supplies are locked up safely in a small tack room that I share with one other person, but my tack trunk is out in the aisle. I don't keep anything valuable in it but I would hope that no one would go looking for something in there. I am very particular about my things.

So my question is, what rules does your barn have?