Well, 5K for one that starts, runs, and has a loader is about as good as you will ever do. And it is a common model. I just don't know that model well. One friend had the next smaller similar vintage IH for many years and it was always fine. However it runs now is probably just exactly how it will for years.... might put it in a high gear with a load and stall it to make sure the clutch isn't slipping.
Put your eagle eye on the engine oil. You are looking for antifreeze in the engine oil. Sometimes water/antifreeze will make the engine oil look brown and cloudy instead of black. An old trick it to fold up a paper towel and put a single drop of warm engine oil on the folded paper towel - blotter paper is even better. Look to see the concentric rings. You will generally see the carbon particles float out round a cleaner center. Sometimes water if it is there will show as a greenish ring (antifreeze).
You might be able to find blotter testing photos on Google, I've not looked. Sometimes I will pull a spark plug....oh, this may be diesel & not a gasser.
Finn, how do you know that is the 3 cylinder diesel? Could be a gasser?
That one looks to have decent matching rubber on the back and automotive tires on the front. I do hope that the power steering unti is working well - check that. Those old ag tractors were borderline unusable without PS.
Is that bucket straight on the front loader arms? Is sure looks like it is sitting crooked... or is that just the photos (both photos). Too bad it is missing the original top link, but at least it has one. Fenders are a nice touch. I always like it when the original owner who ordered it new added a few little extras. Gives it some class.
What are you needing a tractor to do? Just occassional lifting and hauling around the property? That one looks like it will do that. We used an old JD for years for exactly that - and had more than $5K in it in the end.... but not much more. Sounds like you are a mechanic, so just trust your feel - and do check out that bucket for straight. The bushings don't bother me as I imagine you will just be using it for some chores. For that, bushings don't much matter.
If it runs OK and starts from cold then you aren't going to do much better - maybe not as good.
rScotty