I love the modern look of your quilt. If it is in your capability, I would love to see pebbling in the sashing so that the doors and all the applique appear to be floating. Then I would keep it super simple in the doors. I am not a SID person, but this quilt seems to call for all those cross lines in the doors to be SID on each line thus emphasizing the design elements. If you are using a batting where you can get away with no stitching in the leaves, then I wouldn't put any there. (Warm & Natural is 10". Makes it a good choice for me.) Your fabric speaks for itself....maybe just one or two echo stitches around the treetops. The trunks need some strong vertical bark like wavy lines.
Now, which to do first, I don't really know. If I were doing it I think I would start with the SID in the doors, then the echoes around the applique, then finish with the pebbling. All on a machine. I am not nor will ever be a hand quilter.
To test if you would like any idea, you can put a clear something - plexiglass, clear ruler, clear glass, on your quilt. Then put a piece of clear food wrap or tracing paper on top of the hard surface. Next step would be to mark the main elements of your quilt with whatever will write on your top paper or plastic wrap, being very careful to keep the marks on the top paper. Then try your quilting designs. This works for me. If you design something really elaborate, you can even sew through the paper. Most times you can tell quickly if you would like an idea. There are marking pins (think Crayola) that are supposed to be washable & could be wiped off the clear heavy vinyl you can buy at the big fabric stores.
Please post a pic when you do whatever you decide. it truly is a great top.
Edited to add: I just saw this thread. It is a great example of things you can do to make your quilt the best it can be.
http://www.quiltingboard.com/picture...t-t249162.html