There’s an access near Ericsburg off 119 but I’m not sure how big a boat can be launched. I do see a lot of 18 foot plus boats coming and going out of the river and not returning. I assume they are using the access. The only cabin I’ve seen is in the river part way between Black Bay and Rat Root Lake. Flow is dependent on rainfall. The lake is basically a wide spot so it slows down. I’d guess it would have similar flow to maybe Sullivan Bay.
I think James has been in there fishing crappies. He’d probably have good advise.