I've been out at Fossil Trace a few times myself, and almost everyone rides. That said, I played a course up on the north side called Hyland Hills recently that's on a much flatter ground, and most everyone was riding there as well. So shall we characterize that as a cartball course? In a way, it's funny to talk about a "walking culture" at a public course here in the States. Sure, there's a walking "culture" at Bandon, but can you call it a culture if it's mandated? Tim, are there other public courses in the Denver area where they are creating a walking ethic? Perhaps CommonGround?
My sons and I usually play out at a place called Murphy Creek, which couldn't be an easier walk. We usually play nine holes, as their attention tends to start drifting somewhere short of 18, but they're still young. That course creates a walking ethic only through being on a bit of land that is friendly to the walker, having short green to tee distances, and by charging you less if you don't choose to ride.
But from what I see when I'm out there, most ride anyway.
I think that Tim makes a good comment when he says "sometimes when you jump ahead from one part of the land to another via a cartpath in order to use a particular landform, you might miss something more subtle and cool in between. To me, that's a danger of designing for cart golf--there's a tendency to go for the home run and you may end up not taking advantage of opportunities in the transition areas." I think this is a fair comment, though perhaps less so for Fossil Trace than other Engh courses I've played, as FT is shoehorned into a very small bit of property, and I don't know that a lot of subtle, cool stuff was missed there.
But I do believe that Jim Engh wants his courses to take best advantage of the natural greensites and other features that are available on the bit of land he has to work with, and wants to hit those home runs of which you speak. I'd be interested in asking him if he is willing for a course to sprawl a bit, to sacrifice some ease of walking, to hit all of those killer spots that a particular property has to offer. I know that some might consider this question already asked and answered, but I'd still be interested in hearing his take on this.