Skylab B in orbit with a docked CSM (SL-8), a Progress Resupply Ship (Progress Skylab 1), ATM B, and Zarya.
I'm flying the station in an alternate history scenario where I launch the station in May 1976 and keep it continuously manned as long as possible. After SL-8 leaves, I plan on keeping the station manned and supported using Soyuz and Progress craft until the Space Shuttle is completed. I planned from the start to incorporate pieces of ISS with it and Skylab1980 with it. I launched Zarya to it because I wanted a second Soyuz port.
I'm considering disposing of the ATM and replacing it with Zvezda for a third Soyuz port. Hate to lose my solar telescope though.
EDIT:
I think that I can keep the ATM longer if I move Zarya to the top APAS port and dock the ATM to it.
EDIT of an EDIT:
I might have to just forget about Zvezda. Doubt that I can get it up to 434 km.