Hi Mith
I can probably give you some advice 'from this side of the pond' so to speak
You are on to a good tractor here - the JD 50 series are probably one of the most bulletproof for their era.
I've never seen anything smaller than a 2450 and they are a bit of a rarity, a 2650 or a 2850 is what you need.
Once you get into the 3's you go 6 cylinder, clumsier and heavier on the drink.
You'll be looking at the best part of 6 or 7 grand for a decent 2650 / 2850, then prices vary wildly when you get broken ones. I have seen them for sale for as much as 13K, I wouldn't pay more than 8 for one though.
The 50 series (2x50 and 3x50) mostly had the SG2 cab, which is a good quiet cab, but personally I hate it because you have a blemming post smack bang in the centre of the screen, but at least it tides up all the exhaust pipes inline with it! Other than that it is a comfy cab.
They also came with and Operator Protection Unit cab and an MC Cab but but I can't remember what that stood for. Both lower spec but sans annoying centre windscreen post.
None of them had shuttles on the gearbox, so they are not the best for loader work now a days. Are you after a loader as well?
Otherwise a **** good tractor.
Other options are Massey 300 series (super bombproof, probably best stock tractor ever made, but still 」」」);
Massey 3000 series (good line of tractors really, electronic though - some hate them but they are pretty reliable, just don't buy one with a 32 speed gearbox, they will go bang and its a 4 grand fix.);
Ford 6610 is a good reliable 4 cyl tractor, not too many 」」」, lots around, acceptable cab.
Bit more luxurious, Ford 7740 but electric, can get some niggly issues and more 」」」.
You could go a bit older, in the less than 5K bracket you are into Massey's 500 or 600 series, like a 698 or 590, but these will probably have very badly rusted cabs, otherwise the 600 series not a bad tractor, 500 series (which was late 70's) was a bit of a donkey. Rusty cabs, horrible steering, but not a bad yolk overall.
Then theres a Deere 2130 / 2140, predated the 50 series, not bad tractors but not particularly comfy after a long day either.
If all you want to do is swing a 8ft topper how about a Massey Ferguson 165 or similar. Superb tractors, more reliable than a hammer but they are not cabbed and no synchro on the gearbox etc.
Case IH made some decent tractors, a 785 / 795 or 895 were good, XL cab not a bad place to spend a day. 4220 / 4230 were absolute dogs though, back end made of tin cans. British built as well (Doncaster), typical!
If you want to spend less than 4K a David Brown 1390 or 1390 or the 1490 equivelant of about 70 HP is not a bad tractor, Hydrashift can be iffy, but not a bad tractor fo their money, well ahead of the times.
Hope this is of some help, I have rattled on a bit