Just my opinion, but I've never had much luck fishing the Rochester area. A short drive to the east or north east will bring you to Wabasha or Winona. There you have pools 4 through 7 of the Mississippi. Some great spots for bass and walleye.
If you are looking for lake, Winona has some small lakes in and around it that are pretty good for pan fishing.
If you are looking for a big lake, Lake Pepin near Lake City is also great.
If you are interested in fishing Rochester, I'd stop at Al's Specialty Marine and get a fishing report from them.
If you've got short, stubby fingers and wear reading glasses, any relaxation you would normally derive from fly fishing is completely eliminated when you try to tie on a fly. ~ Jack Ohman, Fear of Fly Fishing, 1988