Buckinghamshire is home to the Chiltern Open Air Museum near Chalfont St. Giles. The icon below right links you to the museum’s website. There are four barns on the site as well as a wealth of other vernacular buildings.
Also of interest are the barns with ‘cranked under-principals’ which are found in Berkshire, Buckinghamshire and south Oxfordshire. I have not managed to visit any of these in Buckinghamshire yet, but hope to do so in the near future. The map on the right links to a Google map of the barns in this group that I have traced through the internet.