This seems more like a thread asking what used tractor to buy.
... I'm looking for a 48-54" deck model that has an engine that will provide long life as I have around sunny 4 acres that I have to my in a location that downtime is a real killer. I can easily find 6 different JD lines that fit the bill Manf between mid 80's and late 90's that fall in my price range, which is at the ragged bloody edge of a reasonable amt for such a mower $500-700 I'm hoping for a little help sorting things out :-D
Within that price range I bought 3 tractors a few summers ago. The first was an LX176. I don't think the LX series is too small for 4 acres at all, even though it's less machine than the GT275 mentioned. Like that 14HP Kawasaki engine and hydrostatic trans with foot control. But I hated the steering. Hard to turn the wheel. Maybe mine was worn out or needed lube or some other fix, but ... I quickly bought a 265 (and then a second 265 later that summer).
The second and third tractors were bought because the previous purchase died shortly after I'd purchased it, and I panicked not wanting down time. Tractors this old get sold because the owner was tired of dealing with them. Something atrophies and dies soon after your successful test drive at their house. Ask me how I know.
The "Late 200" series is just on another level. It's a generation earlier, so there's a shift/direction lever instead of modern foot controls, but you get a recirculating ball steering box. I kid you not, you'd never want the power steering pricier models have. You lose the modern trans bypass rod that stays engaged by pulling it out (making pushing possible by one person) and the lever mechanism that disengages the trans for pushing could fail. You'll need a truck and a chain to retrieve the tractor. Unlike the LX series, you gain fuel level, oil level light, hour meter standard. At least on the 265.
So the GT series should alleviate those worries, being next gen, but I'd remain on the lookout for a low-hour 265, 285. There was even an EFI version of the 285, and the 320 had hydraulic lift for the mower deck. The 260 with manual trans is also good. The 240 loses some features.
These 200 models have the 17hp 1 cyl Kawasaki. Nice engine. Noisier than a 2-cyl, but so what? If you don't make a big cut in your lawn the tractor will cut decently even at 50-75% throttle with sharp blades. Any of these can "bush hog" grasses taller than the tractor. Grasses, not actual brush of course.
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Consider mower decks independently of the tractor, to the extent they are compatible. You could be better off buying a cheap machine with a better deck in addition to a better tractor saddled with a lesser deck. And then sell the other machine or keep as a spare, for downtime repairs and maintenance. For the tractors I mentioned, the 240 came with I think a 38" and the rest came with 46", 48", 50" decks.
The 46" (weirdly, it'll be unmarked as to size) and the 50" are the same basic design. Good spindles with bearings that date back to the vaunted 317/318 ... but the small pulleys are down close to the deck. Expect those bolts/nuts to have to be cut off when replacing bearings. The "pulley valley" up top is a water and rust magnet.
The 48" deck is the star. Released later. Large pulleys up high, with slots that act as cooling fans.
The spindle shafts have a grease fitting. Next to
zero grass/mud/water catches on top near pulleys, the deck itself is more robust but does catch mud below, so rust through happens but critically, not near the spindles. I have both 46 and 48 and there's a big difference between the two designs, and the 46 isn't "junk."
240,260,265,285,320,160,165,170,175,180,185 can all take the same decks with appropriate draft arms/lift linkage. Notice that the 160,165,170,175,180,185 are all smaller tractors and could be found more cheaply in order get the 48" deck. (But verify it's as I've described. You know, Internet knowledge is only worth so much.)
Even though the LX series overlaps some years, they are next-gen along with the GT and the decks aren't compatible. Someone else will have to give an opinion about those decks.