Sorry for the duplicate post. The image was corrupted.

Dale, Thanks for the feedback! After doing a bit more reading (and crawling under the house again!) I came up with this arrangement. I think this is better because:
1. It turns the old branch drain into a 3' trap arm, thus removing the requirement for a clean-out.
2. Puts the vent wye immediately after the p-trap of the shower as you recommended.

Of course part of it is a horizontal vent line so it must maintain proper slope.

You can find a great reference tool at the link below that has a 'clickable' map of a house plumbing system.

• Single Family Home Plumbing