Gorilla Glue will not harm the (EPS-expanded polystyrene) foam. It's safe to work with, and you can spray the parts with water to get a faster cure and cause the glue to foam up more to get into all the pores.

Back in the day, I did build a few gremlins with .007 CF laminate behind the balsa LE. It added a good measure of impact resistance. You'll still get dents, but they probably won't go all the way through the wing on LE impacts.