I think all of Wingsley's questions highlight that the TOS shuttle (and indeed most of the TNG and Voyager shuttles) seem wholly inadequate for the tasks the show makes them carry out. If it's a simple ship to shore transfer, then you can get away without most of those things. But for an extended autonomous mission, you really would expect some basic necessities. The TOS shuttle is perhaps the worst example, as the set has a job fitting into the exterior as it is, so you can forget any space for a potential WC or storage areas. I guess you could say there are invisible hatches on the walls and floor for supplies, but I feel things could been simplified with a little door on the back wall. The DS9 Runabout set did this really well - we never saw the aft compartment in seven years (except for a single TNG episode), but we never needed to. The door at the back of the cockpit set was enough.