I would reglue everything I could, reinforce the sides and then, with a dremel router, make a clean edge for the patch. Then I would glue pilars across the hole, bend a patch, cut and adjust it, and glue it in place. Some sanding, color touchups,pore filling, and a full side refinish.
I've made this job (a smaller one) on a es-125 here:
duct tape & a prayer