Thanks for all the replies. There has certainly been a varied response and makes for interesting reading on every person's perspective.

I'll see if I can answer some of the questions and address some of the comments directly later.

I would like to clarify a couple of general points though. This thought exercise is just that...This scenario is not something I would ever really envisioning to occur yet it gives me something to think about when we drive up that route. Walking 200 hundred miles after any disaster is not going to be anything close to easy and I used this upcoming trip to highlight a very worse case scenario where there is a major obstacle (river and possible tunnel collapse) in your path from getting home.

If this scenario ever played out for real, I know that attempting a 200 mile walk home is not in the cards, we would stay put and seek shelter/help in the nearest town or village. In fact, I would be quite content to stay there as the area is actually quite different then most here envision a canyon highway route and as I mentioned last night or earlier today that I will post some pictures after the drive up.