I have a JD 5105 that I use on 20 acres for a mix of farm and property maintenance tasks. It is an excellent, solid basic farm tractor. It is not a lot of fun for loader work or mowing in tight areas, but for pulling a plow or disk, or mowing large fields, it's great. Traction and pulling power is terrific - to the point of easily damaging implements rated for more power than it has. If you get the 5205, I recommend Cat 2 implements for anything ground-engaging.
Do you have farming experience? Have you baled hay, or priced the cost of serviceable hay equipment? It's not cheap, and it requires knowledge to bale hay that doesn't mold. If you can hay all 54ac and have a good market nearby it may be worthwhile, but consider the costs and hassle before you jump in. Does your job have flexible hours? If not, will you be happy doing 6 hours of hay work after you get home from working 8 hours at your regular job? Hay needs to be done when the weather and conditions are right. We bought our 5105 with hay equipment in mind, but realized within 6 months that it didn't make sense for us to invest in the equipment. But we only have 10ac of hay fields. We pay local farmers to do the haying, which works OK but isn't ideal either since we're always last priority and therefore may miss cuttings or get less than ideal quality.
As noted, generally horse people and hobbyists want squares because they can be moved without equipment. We use rounds so we don't have to stack squares by hand, but it limits who we can sell our hay to. Around here, a serviceable round baler will cost $10k or more, while you might get a decent square baler for $2-3k, even less if you're mechanically inclined and willing to gamble a bit. A simple mower like a sickle bar may work if you're doing grass hay only, or in a really dry climate, but if you're doing alfalfa in the midwest or southeast you'll need a mower-conditioner, which is also quite expensive.