Cab is a mustBy the time I realistically get into making hay, I'll have two sons at hay throwing age. Round bales aren't super high priority.
My biggest thought with the cab is honestly health and safety. I'm prone to burning in the sun and would prefer to have my ears and lungs fully functioning as I age. Realistically I'm not going to consistently wear hearing protection or a mask when in heavy dust, and I'm known for forgetting sunscreen. The warm and dry are just gravy to me. I also have little use for the tractor in the woods, so I don't need to worry about cab damage from above.
Buyers who start with an open station and later buy a cab machine very often say they wish they had started with a cab. You will use the tractor more often and will benefit greatly with not having to shower after a 2 or 3 hour task and not having to freeze on the coldest winter days. And then there is noise...I might have avoided hearing aids if I had a cab the first 10 years of tractor ownership!I have a 2007 Branson 6530, 4wd with loader and cab, I bought new and one of the reasons was the Cummins licensed engine (now described as the Kukje engine)....all mechanical. Not sorry.
Recently I was looking for another tractor, used, in the same or slightly larger HP and found used TYMs with a couple of different engines which were built prior to the Branson buy-out. The engines were first class, just not Cummins licensed (Yanmar and Perkins). Thought seriously about pursuing them but being fairly new and distant, I looked for something older and closer which I found in a Case-IH 895 with cab.....cheaper and delivered.
I run a 5x4 round baler that produces at least an 800# bale (weighed one once) and the 65 HP (57 PTO) is necessary for running that baler. A 4x5 bale is said to be heavier if considering that. Square balers have low HP requirements and a 35 HP tractor can get that work done.
The cab with AC and heat and both are nice baling and delivering bales in the winter. 4 WD is pretty common on newer tractors these days and I had a 100 HP JD 4230, 2WD having bought implements for it to use and I can use them with my Branson in midrange gears as was the case with the JD.
Open station tractors are usually easier for a lot of get-on, get-off work and of my 7 tractors (25-84 HP) most are open station.
I bought my farm as a city boy in 1979 and I am still learning something new just about every time I do something. Maybe that's why I like farming.....not boring.....something different every time you attempt something and problems require thought to get solved.
Good luck on your pursuit.....and be safe......don't take chances.
In our area the local farmers who have haying equipment will cut, rake and bale for reasonable fee or % of the hay they put up and so I sold my rake, baler and wagon after a few years...I kept the sickle bar mower for road bank mowing. Disk mowers are better for haying; but much more costly to buy.
I would start with a chassis size equivalent to a 5000 series Deere, a little larger than being discussed I believe. I like a 65 hp class tractor as it is conservative on fuel usage; but sufficient for my needs. Large diameter front tires really smooth out transport across a less than flat field.