I got an email yesterday asking me why I always complained about the city schools. So you're in a trailer, so you're in a closet. Can't you ever say anything nice about our schools?
I suppose there are certain advantages of not having your own classroom. For one, you don't need to worry too much about bulletin boards, as you aren't in any one place long enough to be held responsible. In the case of oddly shaped or preposterously small rooms, there is often insufficient space to even place bulletin boards. Sure, you sometimes have to engage in extended battles to procure a portable blackboard, but if you fail in that endeavor, no one can complain you didn't write an aim on the board.
My nephew attends a suburban high school, and his teachers all have their own classrooms. He's a very motivated, pragmatic kid--a real problem solver. One of his teachers was frequently absent, and left SAT prep work when she wasn't there. He (and his classmates) considered it busy work. So they decided to take action.
The teacher always left a sub lesson in her top drawer, and the kids had seen it removed by various substitute teachers. The subs, though, often arrived late for first period. So whenever the teacher wasn't in the classroom, my nephew removed the sub lesson plan and replaced it with his own, instructing, "Show a video." There was always a TV with a small library of videos in back of the classroom, and one kid would choose one and insert it into the video player before the sub arrived.
So, if you're teaching in the city, and you're in a trailer or closet, consider how lucky you are not to have your own room, or a TV, or a computer, or a bulletin board, or a blackboard. While these sort of shenanigans occurred in my nephew's school, they will never, ever happen in yours.