I have a "what if" version of the L&B, but mine is based more on one of the branches being built, and the line surviving its demise, if only for a few years. Mine is circular, with 3 versions of each train, one up, one down and one in fixational livery. I also have modelled various what if versions of the stock, in suitable liveries, based on the existing models, including a CCT wagon.
10ft sounds huge until you start to put things down, the L&B's "mainline" ethos, Pilton does give you a chance to model the turntable though, as they rolling stock and locos may well still be turned to ensure even wear and tear....
I shall look forward to seeing a version of your trackplan!
Chris T B