Layout Design for a Newbie

Nope - not boring.

From a global perspective on what features to potentially incorporate into your layout, I think being able to look at videos or actual layouts (large train shows) of others who model the same basic area of the country you're looking to model is extremely helpful and will give you many ideas for a starting point.

For specific items, see if you can get a catalogue from a company like Scenic Express - not only do they provide a source for purchasing the items you need, but they also show pictures of larger scenes that those items can be incorporated into. 

Thanks Richie.  Good ideas.  I just downloaded the Scenic Express catalog - it will be helpful.

Keep us posted on your progress.

I hate to be the one to burst your layout bubble, but what you ask above is like trying to cram a size 15EEE foot into a size 6DD shoe.  So, let's start with a reality check.  The Museum of Science and Industry in Chicago only models from Chicago to Seattle in 3500 square feet in O scale (at least it used to be O scale), and even it leaves out most of the actual towns between the two urban centers.  Instead, it depicts a number of industries served by rail and has lots of room for scenery.

So, my suggestion is for you to first scale back your "druthers" (dreams) to more closely match your "givens" (your space limitations).  For example, if you really need to model Burlington, IA, then create a plan that makes Burlington a centerpiece of your operation on the longer side of your "L".  Designate it as a Division Point where crew and engine changes have to be made as trains (passenger or freight) pass thru, requiring a roundhouse, engine servicing and small yard nearby.

Next, don't hinder your own enjoyment by designating and designing one loop as just for the grandkids.  Build it the way you want it, but create safety features (a way to cut off the outside loop from the rest of the railroad when they are running) for their enjoyment.  That way, you can run trains in a true double-track fashion when they are not around.

Finally, with a 5' width, the largest curve you will be able to use is O54, with something smaller on the inside loop where you will be running passenger trains.  Most here will recommend using at least O72 curves when running passenger equipment (and 4-8-4s) to avoid sideswipe and rounding corner damage.  With O72 as a minimum (your inside loop), you outside loop will have to be at least O81, which should make it highly unlikely for the grandkids to send anything to the floor.

If you have more space available, let us know and maybe something better suited to your druthers can be developed.

I’d ditch the outer aisles and widen the inner one. This will allow for wider radius curves or the curves you have with an added straight portion. By bumping the layout up against the walls. You can install backdrops with a flavor of what area your trying to model.

Dave, thanks for the input.  I can't do as you suggest because those walls have plumbing stacks and ductwork that has to remain accessible.  But, good idea.