Depends on how accurate you want the end result to be. You can just put 2-rail wheelsets in, and use wood shims to put coupler boxes on the body.
Or, like K-Line, you could look for someone who has cast a bolt-in bolster casting, and use real 2-rail trucks.
The K-Line was really close to the Lionel 716, so bolsters became available for a short time.
My question: how come Lionel will make hoppers out of die cast, but won't do die cast Diesels? I would be forced to buy a die cast PA or E7. Forced!
