Personally, I like being able to walk around my entire layout. One reason, is the ease of working on any part of the layout, another is, and don't laugh, when you get your trains running, and you always watch from your control panel, you are going to see the same things over and over and over. I found that it is pretty entertaining to get the trains running and then walk around and watch them from a totally different angle, perhaps from the farthest diagonal corner of the layout. It gives you a completely different perspective, and to your eye, it looks like a totally different layout!
Two feet is not enough gap space on the side of the layout to comfortable work on and watch your layout run. I would consider 30 inches as a minimum. It will also give you enough room to walk around and go underneath your table to wire up switches and power lines, without having to crawl underneath your whole table every time you need to work on items on the back edges. (You can't imagine at first how much time you will have to spend underneath your table, on your back, to wire up everything and then constantly de-bug problems to get things running perfectly!)
I didn't go for the absolute biggest layout I could build. I went for the one that was "big enough" and easy to work on, service, and enjoy. (5' x 9.5', with a 32 inch walk around in the back.)
Personally, I don't care for train yards, because they take up alot of room and require alot of costly switches and wiring. BUT, having gotten my layout running, and having purchased 5 engines, I can now definitely see the wisdom of having a small yard, with just enough switches and short yard tracks to park your engines and tenders only! The small yard shown above would definitely fill the bill.)
I hope this helps.
Mannyrock
