Scott, qreat questions, I can only answer a few, since I have not stayed at Mt. Vernon for many years ( though agree on your assessment of the road back then).

3 Grand Case still has a Tuesday night event- the last several years it has been quite busy, a small parade with dancers and drums and lots of vendors - some food some small wares, and lots of folks.
7. As far as I know Bae Rouge has no food drinks or chairs, other than what you bring.