Here are some shots of how I routed my harness -
First, along the right side of the frame tube -
Then I dropped it just under the air cleaner cover grommet-
Then continued it under the rear grommet and back up between the fender and the seat support-
Though it's hard to see because of the carb and air cleaner, it drops down for the alternator hookup like this.
Actually, the wire that goes from the harness to the ground terminal of the battery will determine the exact placement for you. It's sort of short, so it will let you know where it needs to be, then the rest of it all just follows from there.
Hope this helps.....