Eric and Bruce,
Thank you for the suggestions, and especially for the layout diagram, Bruce. That is pretty much what I had in mind and I think I will loop the switching lead around as you designed. Connecting the mainline loops will require four more switches, so I will have to save that step for later.
Hatches aren't necessary because the benchwork legs are equipped with heavy-duty caster wheels. The entire train table rolls away from the back wall easily for 360-degree access.
I wanted a switch yard so I can operate the Lionel PRR Legacy NW-2 Switcher that I ordered from the new catalog! 
I don't have plans to buy a big steam locomotive as I like to stick with Erie/E-L, B & O, and PRR around 1959-1960. I grew up in a house situated alongside the Erie NYC-Chicago mainline in Tallmadge, Ohio and watched high speed passenger and freight trains fly past our dinette picture window. There were SO MANY trains running on those tracks back in the 50s and early 60s! I only wish I possessed the foresight to take pictures of the many styles of locomotives that were a routine part of daily life back then. Memories will have to suffice.
Bill
