One way it can cost you space is if you buy a swivel base and can swivel the passenger seat. Doing that gives you a great recliner to lounge in and many people love theirs!! Or you can just turn the seat around and bolt it on backwards, which also gives you a recliner. Again, I know many people that love that. You do have to be sure you can still see the mirrors with it turned around though.
I have a friend that was able to take his seat out and put in a small recliner that he loved, but that isn't always possible--often the doghouse is in the way.
A way the bulkhead could help you is to get a tall, thin bookcase and bolt it to the back of the bulkhead on the passenger side. I have three milk crates stacked up behind my bulkhead (ratchet strapped to it) and my inverter bolted to the bulkhead above it. I have a coat rack in the front of the bulkhead with rope, a hose, electrical cords hanging down tucked in behind the seats.
So the bulkhead can be great if you leave it in, or great if you take it out. Just whatever your priorites are.
Bob