Help, found cancer during cleaning...

i wouldnt jsut bandaid it but thats jsut me. do what you need to do to get it fixed and in great shape and youll never have to worry about it again. Im sorry i cant help you with your problem as ive never done a huge amount of body work but i just wanted to chime in with my .02 cents.

Bandaids on bodywork is what got your car to the point it is now. You need to replace the bad metal with good. A rocker panel is not the easiest to replace, nor is a wheelhouse, but they can both be accomplished by the hobbyist if the right tools are procured and you get someone with some experience to help you. I have done both and you can achieve fantastic results with a little patience. If you have any good Mustang clubs in your area maybe you should join so you can meet lots of people with varying degrees of experience. You may be able to find someone to give you a hand.