[like] Sadly, my TARDIS is for storing junk. It is so full of boxes and stuff that the door barely opens (sidebar: Actual police boxes, the door does open outward. On the downside, a ne'er-do-well could trap you by putting something against the door, but the inward opening door costs me almost 25% storage space. And actual police boxes had aggressively sloped floors for drainage, so an inward opening door wouldn't have worked.) But when I first built it, I did pick up a package of cheap styrofoam plates and glued them on the inside walls. The effect was pretty neat--until they became a magnet for mold and rot. Besides, not that I cut my windows all the way through (at first they were just painted primer grey plywood with frosted plexi glued over them) it's hard to do a convincing interior. If anything, I think I'll do a Google Sketchup interior.