Chris, I actually like the first track plan the best except for that three foot long removeable bridge. Things like that give me the willies. You could bring out the the benchwork about two feet over the desk, rearrange the industry tracks on the other end, and have enough room for a loop at either end so you wouldn't need the bridge. Riverrotter has a good point though. What is your railroad supposed to to and how does your track plan help the railroad accomplish its purpose?
I like a mix of the first and second.
You should come up with a random thought for a layout about the size of the thing I am working on now.
its about... oh a 2 foot wide L, 8 feet by 5.5 feet
There you go, 2 feet wide all the way around (not much extra room in here).
Min radius can be 18, although I would like some 22"
I pretty much thought about switching layout, although, I may find a way to make a loop.
Also, I thought about the main line being across the back