Hi Bill (CN Fan)
Welcome, you'll be learning lots from this forum so I suggest getting started through the threads. :mrgreen:
I, too, lack space (still staying with my parents) and I'm busy building a HO Portable Layout. Mainly for shunting (switching), it will be 4m x 0,40m and based on the railways here in South Africa.
I'll be posting some pics soon in my blog, so take a look there if you get the chance, maybe you can get some ideas or even improve what I'm doing and we (The Gauge) will be able to help you accomplish something, even if it's a N/Z scale coffee table layout.