RC CARLS -
I had a few more thoughts about your situation this morning. Pardon me if I am blunt.
3 point implements are pretty much universal. Backhoes are another matter entirely. Due to the strong connection needed between the hoe and the tractor, manufacturers have engineered specific attachment systems.
Getting a "good deal" on a John Deere backhoe to put on your Ford tractor is about like getting a good deal on a Chevy engine to put in your Ford truck. Can it be done? Yes. Does it make sense? Probably not.
If you were dealing with a newer Ford/New Holland tractor, I would recommend looking for a backhoe subframe specific to your tractor and trying to marry the JD backhoe to it. I don't know if a 3rd party backhoe maker, such as Woods, would have a subframe for your tractor, but it might be worth a try.
Did you get the "tractor side" pieces of the John Deere mounting system in your deal? If not, you might be able to track them down. I'm reasonably sure it's a two-piece system that bolts up to each side of the tractor's rear end, instead of a subframe that goes under the tractor. Having those pieces would give you a jump start in fabricating your mounting system.
Are you skilled at welding and heavy metal fabrication? If not you should hire it done by someone who is qualified. The cost of this is another reason to reconsider.
I don't think your project is for the faint of heart, or the light of wallet. You may want to cut your losses and sell that "good deal" to someone else.
Either way you go, best of luck to you. If you go ahead, post some photos of the project.