You can always make it a plundered house, with most of the items stolen and the rest smashed to pieces.
For other interior items, you could make chests, a bookshelf, a weapon rack, barrels, a carpet (as a painted piece of paper), hay as bedsteads, etc. For an inn, it would be already sufficient to have a little hay on the upper floor (sleeping hall) and a couple of long tables, a big barrel and a bar on the ground floor, I'd say.
And even if you don't have anything in it, accessible buildings really enhance your games. Oh, and don't forget the windows, of course, for good sniping positions.