I understand, but you still have to consider how your spot affects the access you speak of. Are you saying that if you build within the 9x17 space that all the other requirements are taken care of as far as access? In that case, I'd probably do a 30" rectangle and have some kind of lift-bridge to walk inside at one end. You'll have space for nice long runs and easy access to anything on the layout.
Yes, that is an accurate assessment of where my head is. Thank you, John. BTW, do I understand correctly that are you associated with Henning's in Lansdale? Would love to make a day trip up there some day to see the place for myself.