OOOPS!  I mislabled my drawing and the post so far as the area being modeled is the "Mission Spur"...when in fact, it futher down the road and actually the "Chatsworth Spur"  I'll update the drawing, but for all intents and purposes the layout is the same, it's just become the "end" of the line instead of smack in the middle of it.

Here is a rough schematic view of the parts that have been built and tracked.  These were done several months ago, just got them out of storage and will be working on them in between pressing side jobs.  What isn't included in the original plan was the Signal Oil Depot, but I thought the splash of yellow and black was too cool to pass up.  The Chatsworth Spur measures 4'x 3' and the Run Around is 14"x6'.  All the straight tiles will be this dimension going forward.  I was going to just force track centers to mid point on the flat, but that limits what I can do.  Besides, I don't see the need to mix up the tiles in the future.  The Staging yard will be a clip on piece and not landscaped...but painted all black to make it less obvious at shows.  This piece will be 4' long.

Here is a shot of the first scene I am working on snatched from the Pacific Electric Railway Historic site.  Called the Chatsworth Spur it was a pair of packing plants that were located right off Brand Avenue towards the middle of the line.  As with Bruce's design, this will be the anchor module and to the right will be a removeable section that will serve as staging track and room to  move cars back and forth.  I joined two modules together to get the correct shape, a funky corner piece with a wedge taken out and a 4'x14" straight section welded to one side.  As it happens, two parts designed for another section worked out well for this application.  

Showcase Minatures makes an HO half model of the wood sided building to the right. Showcase  As it happenes this kit will almost fit the area I have maped out, but will instead scratchbuild my own to save time and money.  The one on the left is unique and there are only a few photo's of it I could find on a google search.  Enough to get the concept down and make something.  As with any modeling, eventually you are faced with proto/fantasy and near enough, or build something else.  This will be a cool scene expecially with the large tree out front, the double street crossing and the busy details in the yard.