The self-guided tour through the State Rooms typically takes between 1.5 to 2 hours. The Changing the Guard tour involves significant walking. Your guide will lead the group on a route to get the best viewing spots. The tour itself can last up to 90 mins and does not include entry to the State Rooms, the Royal Mews, or The King’s Gallery. The amount of walking on a walking tour that includes Westminster and Buckingham Palace depends entirely on the specific tour you book. Most of these tours are designed to be comprehensive walking experiences and can last anywhere from 2 to 4 hours. They often cover a distance of 3 to 5 km, visiting landmarks like Westminster Abbey.