I think I might be getting a bit carried away with this project...
Dining room/cafeteria. I discovered you can get a panel of carpet to apparently hover in mid-air if you place it on top of another carpet panel, so that's how I've made the table tops. It did mean the dining room had to be carpeted though.
Counter. Glass blocks are supposed to represent those glass things they put food behind in cafeterias. The upside down steps are meant to be where you put your tray and slide it along. Item frames are so useful! (I originally just had random paintings up there)
Cash register. The pie is a lie.
Main reception lobby. The two pairs of doors to the right of the desk are supposed to be elevators. Obviously there aren't any actual elevators in Minecraft so it's actually just a shaft with a ladder in it. The doors do all open when you press the button though!
Pigeon holes for snail mail (Well item frames full of paper, but who's counting?) Obviously the pigeon holes would be packed far more densely if this wasn't Minecraft but it gets the idea across at least.
Payphone booths. Even with item frames there's just not really anything that looks much like a phone to that'll have to do. Maybe some student smashed the actual phones off the wall whilst on a drunken bender and just left a mass of wires where they used to be?
Oh well, this bunch of millennial hipster snowflake students are too busy candy crushing their iThings and crying about Brexit to know what a pay phone is for anyway (I'm kidding!).