My buddy had access off I think it was County hwy C. This was like 30 years ago. There was a long stretch that was 4 to 5 feet deep. I imagine any place where there is some deeper slower holes should hold fish. Tiefsa caught some on one of his YouTube vids. Lime kiln might hold some.
Milwaukee River at Thiensville

in the fall, I always launch at village Grove launch, I go north to the steel wall, if you see it, you know what I mean. I tried going further north running my big motor, but had trouble. maybe with the trolling motor I'd be able to go further north, but we catch all the SMB we want in that stretch. I have a 16.5 lund with a 50 hp motor.
Greetings
I grew up in that area. Several good friends fished the river extensively. Basically from West Bend down it is a kayak or canoe river. There are some short stretches where a bigger boat will fit. Those are very short pools. Look it up on Google maps.
There is a fair amount of small to medium SMB, a few smaller NP, and fairly good catfishing.
If your after bass with a bass boat there are probably better places to fish.