We have the same problem or situation in this area at times, though actually over longer periods time if you look carefully, you will find what you are looking for in the condition you need at the price you want, or within an acceptable range. Problem is, with immediate needs, you may not find the above, I peruse the ads daily, so its what I have observed. With all kinds of things I have acquired over the years, many were not right away, just keeping an eye out, being in the right place at the right time with available funds.
In my case, I wanted to relive my youth a little, live on a nice piece of land and can use one of these at times, so I saw the D7 for sale, 1200 miles to the west, sight unseen, took a chance, but it was as per the description, even if not, at the price, + the $1500 shipping cost, if I got something that was scrap, I'd have lost some money, but not all, about a 1/3rd at worst, I took a chance, and I did get a very low hour tractor with a hardly worn OEM undercarriage.
I think its a decent option, looking out of area if the price is right and you can afford shipping if its something that matches what you are looking for, even if you do pay more over the top than you want, better to spend a little more for something in better condition.
I would venture to guess that if the tractor shown in this post, just needed tracks, rollers, idlers and sprockets within tolerance, it would be worth doing, maybe there is adjustment left, with better chains, (links, pins/bushings) you could retain or gain more adjustment, it would be fine for what most of us do with these, which is not 10hrs/day 5 days a week, better to rent or own late model equipment for that kind of use.
I was glad to see Old Magnet take a look, stating that undercarriage parts are available for these, that improves the value of one of these for sure, its still costly, but at least you can get it, can't for the D7 of that era or so I believe.