Good for you, hope you can follow through with the plan. Need a survey of old barn - might be great, might be a nightmare. Might save you money (rare) or it might cost you more than "new" frame. You have LOTS of options. First step - find a timber framer (from TFG directory) in your area and pay them $100 to take a look, covers fuel and is polite for the 1-4 hours they will be giving you. See if Leon Buckwalter can pay a visit, or Rudy Christian - I know there are closer folks but don't have any names at hand.
A few TF shops specialize in working with old stuff. Some fix it as it is, others take timbers and cut a new frame out of it. If it has to come down and be moved that requires some special skills. Don't worry about trucking the frame a ways, the few grand of trucking is small part of your cost.
Lots of us can help in one way or another. You need a survey first.