If you ever happen to be hanging around Frankfurt in Germany and have half a day to kill I can highly recommend the
Auto & Technik Museum Sinsheim. They've got Concorde F-BVFB mounted on poles on the roof of one of the exhibition halls alongside a TU-144, both are open to walk through. The cabin is intact but they have removed a large number of the seats to provide open space and put up exhibit info boards but they have preserved every few rows behind perspex. The cockpit is also behind perspex. Still, well worth the experience if you're in that neck of the woods and there's a hell of a lot more at the museum that makes the whole experience even better. I went on a particularly nasty, drizzly day but
managed to snap a few photos