Hey artlover2, we just finished doing so. Our company works out of an old mansion that is now the lodge of a camp and we use the entire upstairs to store costumes and props. We have no set system for storing things, but do just have one big list for inventorywith the list split up into furtniture, hand held props, mechanical things, and peices that can be used for other building projects. You should think about splitting yours up according to time period, a few of  our rooms are split up like this since most of the shows we do have their own speicific time period. I am certain you are looking for a more specific answer, but i figured since no one else had answered, any little bit would help.