Good Idea, that might work.

 Are you suggesting a blue outline perhaps? cuz that would be my solution if not wanting a full background.

Sure it is a nice Idea but I feel something is missing and I'm not sure about the colour choice either... It doesn't seem to work very well with the PJ grey. I understand that you try to keep those wonderful autumn colours.

Two of the things that help to make the reds so wonderful in my opinion are the cloudless blue sky and the vivid leaves/gras which haven't turned yellow/red yet.

Warm <-> Cool

Check this out.  (Huge pic)

It has potential, just try to get vividness.

I hope this helps.