I am in awe that you did a king-sized quilt for your first machine quilting experiment! You go girl!! I would love to see the quilt - can you take digital pictures? If you can I'm sure we could walk you through posting - I am definitely NOT a computer whiz, so I know you can post pics with little prior experience.
As to quilting it - I think I would go with bearisgray's handquilting around the appliques idea, if it was me. I do like Knitette's idea of the little quilted accents in the appliques...but then you have to stuff it into the machine again. (Good upper body workout, though.)
Good luck!
Alison