Under body rust repair?

[tvmax1962]

Is there a book or preferable video that tells how to repair rust/replace pieces on the underside of a Mustang? I have a 1968 convertable and there is quite a lot of rust where the rear suspension bolts to. If tis is difficult does anyone know a shop in central Missouri that would do this type of work? Would a normal body shop handle this kind of repair?
Thank you
Jim