Jon , try a company called Lord Fusor. They make all kinds adhesives for everything,even difficult to do plastics they have an adhesion promoter that allows their glue to adhere to anything. F-150's body panels are glued together with it . Bret
Frame rust THROUGH on a 6 or 7 year old truck frame is not normal. It is good that Toyota takes care of it . The rust coating they provide now only lasts 1 year.