We were just there first week of August and yes the stables are open for visitors. Not staying at the fort you could park at MK and take the boat over from the main entrance. It is running. If you wish to drive to the fort just stop at security and tell them you are going to the stables and P&J’s takeout. You will have to park in overflow parking and ride an internal bus to Pioneer Hall. Any color bus will drop off at that location. From the drop off at Pioneer Hall the stables are visible and a short walk away as well as P&J’s and The Settlement Trading post for quick shopping.