Nice find. June's upholstery makes some nice speaker pods which would take care of the speaker holes just fine.

There are rear speaker wires under the seat that are going unused.

I added the Kuryakyn trailer harness (Kuryakyn part #7676 and #3234) and a flat trailer disconnect harness to power the lights on my tour pack.

If you are going to keep the tour pack on your B, you could also use the antenna on the tour pack.