You can put an awning rail just below your clearance lights. Make arms much like Zip Dee arms that attach to the coach via a bracket riveted to the coach and in place of bolts, use 1/4 pins. At the coach end of the awning material sew in the same flexible plastic they always use. At the outer part of the awning material, sew a pocked about an inch wide the full width. Make the awning about five inches longer than the pocket to allow for the part that hangs down. Drill a 25/64 hole hear the outer end of each arm. Get some 3/8 inch aluminum dowel to slide through the awning pocket and the arms. Make it a little longer than needed, drill holes near the end and use hair pin clips to keep the arms from sliding off the dowel.
To hold the awning out from the coach, make two stand-off rods that are in pockets along each end of the awning.
To put it up, slide the awning into the rail, attach each arm to the coach, slide the stand-off dowels into their pockets, slide the arms onto the aluminum dowel, secure with the hair pin clips and you're done. To remove, reverse the procedure, put it all together and roll it up. You can roll the arms and stand-off dowels up inside the awning. You can leave the outer dowel in the pocket.
It will be completely independent of your rear window.