Hi Steve...
<font color=blue>I have no justifiable reason to have a barn, but I WANT one.</font color=blue>
You may not be able to justify having one or building one but it's likely you would find a ton of uses for one if you had it. Some use examples: storage for all those things you no longer have room for in the house, store your cars and tractors, woodworking projects and the like (such as a woodworking shop).
<font color=blue>Sadly the barn will probably fall down before it is restored.</font color=blue>
Have you thought about offering to purchase it from your neighbor and re-erect it on your property. 4 acres is fairly large and would sure accommodate a barn easily. Or better yet, maybe your neighbor will just give it to you free of charge if it's that much of an eyesore and if you take it down. This type of arrangement is often done throughout New England. If it's a smaller barn, it may not be all that difficult to take apart and put together on your property. There are contractors around that do this kind of work. I see from your profile that you are in Massachusetts. I know of a fellow in Buskirk, NY (not far from Mass) that does this work for a living. If interested, he could likely give you a quote for what this may cost.
Don't quickly dismiss the idea of a barn. These are highly versatile structures and if you had one you'll likely say to yourself "How could I have ever gone so long without one?" /w3tcompact/icons/wink.gif
BTW, congratulations on your recent wedding. Many joys and best wishes to you and your bride for many years to come.
Bob