Sounds like your heart is set already on following through with this project.
Recently my bro called and told me he had broken the drive side dropout on his DeRosa road racer. We discussed options such as replacing the one or both dropouts. After a few minutes of this I asked him how many miles he had put on this fabulous old race bike. He calculated for a while and came back with the figure of minimum 120,000 miles.
I advised him to kiss the old girl goodbye and hang her on the wall. Reluctantly, he concurred.
The moral of the story.
Bikes are engineered machinery. Unless there has been some unanticipated stress on one specific part of a frame to cause a specific failure, a failure of one part generally indicates that the rest of the unit is near the end of it's wear cycle.