This is my version of the loop (start around the 2, end around the 16). The ending varies a little - I'll either take Island Dr to Riverside Park and then hop on Broadway, or I'll ride around through Fuller Park a little bit, then take Fuller/Depot to Broadway and pass near the start of the loop again.
Since there's no official map, I was wondering how different it is for you guys, in particular the part connecting Cedar Bend Nature Area, through Fuller/Island Park, to the Bluffs (#15 -> #16 -> #2 on my map). I saw some trails next to the train tracks between Fuller Rd. and the Huron river, however, I can't figure out how to get there.