The standard group tour of the USS Missouri takes about an hour.   It is a guided tour.  After the tour is over, you can wander around the ship, although only about 5% of the interior of the ship is open to the standard tour customers.  The crew's quarters, admiral's quarters, captain's quarters, radio rooms, machinery spaces, galley, and most other interior spaces including restrooms are closed and off limits.  You can see into the bridge (where you steer the ship) but it is roped off.  You cannot go into the gun turrets, either the 5 inch ones or the 16 inch ones.  The ship was updated in the 1980's and it is not in WWII configuration.  There are no anti-aircraft guns, for example, and no aircraft, and there are many other changes.  It also has been outfitted with more modern weapons, including cruise missles and Phalanx.

The "Explorer's Tour" and "Chief's Tour" include visiting more of the ship, including a 16 inch turret and the engine room, but at a substantially higher cost.