John and I spoke for well over half an hour this morning (Saturday, 11/12), and he showed me where they plan to put in the garden railway. It's essentially flat and has to be the better part of an acre -- although local planning and zoning rules might make the actual available space a little smaller. A 7 1/4" gauge loop of track occupied the space before. And live steam is definitely going to be part of the plan, there are Society members (and others who have been consulted from outside) who are in favor of it.
As John explained it, the big issue for having live steam at the established Railway Hobby Show every January was crowd density -- too many people too close together for safety. He implied that the fire marshal might take a more favorable view for the April show, which theoretically wouldn't have the same sized crowds. Nothing's definite yet, so there's time to lobby ARS. Watch this space!