All this sounds like you were almost in heaven Bob. What a great thought and execution by Joanna! Sounds like you had several fully packed days.
Ref your conclusion, yes you really must visit Memphis and New Orleans, but I recommend doing it the way that we did join them up with a nice slow drive through Mississippi visiting all of those places we have heard of via the records. Clarksdale is the most obvious stopping off point, but there is so much to see - Dockery farms etc. You know it makes sense.
The blues are the roots and the other musics are the fruits."Willie Dixon'