A: easy to gather research for
B: Works well with nature elements
C: Have enough depth for a FMP
Whilst thinking this over I remembered a place called Calke Abbey in Derbyshire where I went to take some reference pictures for trees etc.
"Set in the midst of a landscape park, the National Trust presented Calke Abbey as an illustration of the English country house in decline. A massive amount of remedial work but no restoration has been done and interiors are almost as they were found in 1985 so the decay of the building and its interiors has been halted but not reversed. Before the National Trust work of the late 1980s everything had remained untouched since the 1880s. The Trust manages the surrounding landscape park with an eye to nature conservation. It contains such features as a walled garden, with a flower garden and a former physic garden, now managed as a kitchen garden."
For me the area most suitable for my project was the stables.
They already exist in an environment very similar to the one I want to create. So from the begin I can be fairly sure the scene is going to work.