Buckingham Palace in The Crown was assembled from several filming locations. Netflix identifies Wilton House near Salisbury as the production's most frequently used location for the palace, including its ballroom and formal dining room.
Lancaster House supplied state rooms and the Queen's office, while Wrotham Park was used for the audience room. Elstree Studios provided other interiors and exterior sets.
That means a visit to one house will reveal only part of the screen version. Wilton House has public visiting arrangements, but opening dates, ticket access and the rooms available should be checked directly before travelling.
Netflix's location guide is useful for matching a scene to a building. The venue's own website is the place for current visitor information.