I can tell you that all of the St Johns south of Lake Harney is low but still fishable. The only hiccups that I know of is getting into middle river from Lake Poinsett and getting into Harney from the river. There was only 6-8 inches near the mouths the last time I was there. No issues with Washington and I haven't been to Winder so can't help you there.

Isn't Maryville right there by Gatlinberg? Those mountains are probably the most beautiful place I've ever been.