The entrance to the State Room tour is on the left hand side of the palace through tents set up just for visitors. Not surprisingly we were guided through security before we could get inside the building. We were also advised that no photography was allowed on the tour so I've found a few photos online to remind us of what we saw.
It took an hour or two to walk through all of the rooms open to the public (if only we could have looked behind some of the locked doors!) and at the end of the tour we were directed out of the rear of the building and into the gardens.
We couldn't actually walk in the gardens or on the grass but it was a nice walk along the paths and out of the exit at the rear gate.