Last I knew it was all floatable, fishable, free access somewhat limited - Pineville City access (not very wadable), MDC Mt Shira access near Ginger Blue and MDC Cowskin access at the Mo43 bridge. The camp people might fix you up at other places. Running over 500CFS your big boat should float in most places. Entire river from beginning to the OK state line is a bass special management area, https://huntfish.mdc.mo.gov/fishing/regulations/special-areas/elk-river
Map= https://huntfish.mdc.mo.gov/sites/default/files/downloads/area/Elk-River-SMA.pdf
Flies- gurgler, pigboat, deciever, Tap's Bug