Brian,
Thanks for sharing your trains with us! And your Izzy too! My layout is in a perpetual state of "in process" and consists of bare foam and wood with a few scattered buildings and vehicles. It measures 18' x 11' with a duck under to access the inside tracks of the three loop pattern. I figure if I cannot crawl under it, it's time to sell it all. I'm limited to a large room in the basement and a shelf or two in the den.
And you can't beat a rescue dog. Our Carmen was (as far as we could determine) a Border Collie/Shepherd mix and was the gentlest dog you could ask for while also being the most protective of our kids when they were small.