Here's a quick reaction to your track plan. First some general
1. designed for only one train in continous operation
2. only one turnout is effective in counter-clockwise direction of
3. relatively complicated (to me, that is) return loop concerns
4. good candidate for DCC ;-)
Warning: my suggestions are based on my personal preferences and have
nothing to do with any knowledge of layout design.
You can see from the annotations that I made to your original track
plan that I like to see two trains running or 1 train running while
the sole operator (you) moves a second train around the yard areas.
Adding the long blue extension to the main line will provide a
bypass at the yard throat where you are likely to want to operate a
switcher or pull a passenger train out of or into the yard. Most
railroads would avoid having trains pull directly into the main line
from a yard throat.
Keeping the single main line to the Right Hand of the plan provides
additional operational challenges that you might wish to maintain in
the plan. Later on, you can always upgrade the layout to complete
double main line if you so desire.
I like to run trains to get the kinks out. My suggestion to you
would be to simulate running trains on paper or via a computer
simulation program or go ahead and lay the tracks and run trains in
the manner that you plan. Find the weak spots and correct them
before doing a lot of scenery that you might have to remove if you
want to correct trackage.
I'm sure that you will get lots of enjoyment out of this layout,
Kari. Thanks for sharing the plan with us.