I have a few suggestions from someone that lived in Winona for 20 years. For the most part forget the Winona float. The floats at Alma and Dresbach are always worth a shot. At Dresbach, if you don’t mind crawling down the rocks to the shoreline it is also worth a shot; also under the bridge can be decent there. For catfish there are barge docks below St. Charles Street that at worth a try as long as a barge is there unloading.
Lake Winona produces some nice bass, but you probably need something that floats because of the plant growth in the lake. For panfish try the Winona Boat Club.
Trout fishing is always decent and if your new to Winona start with the middle branch of Whitewater.
If/when you decide to buy a boat send me a personal E Mail because my suggestions would be quite different. There are just so many areas to explore with a boat depending of what type of fish you are after.