One thing did occur to me about what you mentioned. If the bathroom doors for men and women are placed backwards, the sim of the wrong sex will be able to go in. But then they will be trapped, of course, because when they are on that side of the door, it will be locked to them.
I do always place my toilets in a 1x2 room, with either an archway or a door. It seems to keep Sims from barging in on each other somewhat. The showers can be done this way as well. It also doesn't give enough room for Sims to stand and chat together.
As for the Clubs, I do have one question. Do you just have one Club? If you have two, and the Leader is the same person for both, you can't have them running together. You need to make a different Leader for each of them, then they will run simultaneously. One thing I have never done, tho, is try to have the Club Members locked in during a Gathering. That indeed might have something to do with the gatherings ending. The thing is about Clubs, members will never leave the lot until you end the Gathering. So locking doors is not really necessary to keep them on the lot. The game mechanics might be confused by this. But I do understand that you want to keep them in the certain room. I hope you can figure it out.
