I don't want to "bust your bubble", but i live in Mississippi. For the last 10 years or so i've asked every older black person i've had a chance to talk to if they ever saw Robert Johnson play. None had ever even heard of him. I did find a white guy who said his father played with Son House one time! He was mostly forgotten for 50 years here until the CD box set came out. As for the grave i saw an article in the paper last year that said some old lady remembered him being buried and showed his son where it was cause there was a big lawsuit over the royalties. It wasn't even in the same cemetery as they thought. None of the places he played are still there as far as i know.