STOP! Before you go slapping Bondo everywhere, a couple questions. What is the year model? Is it is a classic and you want to salvage some sort of authenticity? If so, check into lead filling.
In the stone ages of body work before Bondo, lead filling (actually a type of solder) was used for repair. Trust me, it will add big $$$ to the resale value and is relatively simple to do yourself. Or you can smear Bondo all over it and head to Earl Scheib's.