100-125 ac is sizeable land. Here's something to think about. I mow with a 10' mower, don't overlap much, and mow at a pretty brisk speed. Takes me about 2.5 - 2.75 hours to mow about 10 ac.... non-stop.
You will want a minimum of 50 hp for a 10' mower.. preferable more.. and probably a bigger mower.. 10' being
-minimum-. More like 12' or 15'.. course.. those can be cost prohibitive ( although i hear that howse is comping out with a 'copy' of the flex15 mower ).
Now.. all that said.. as you can figure.. the big tractor that does the big work.. may not be suitable for the little work.
Brands aside, some peopl eopt to spend their money on a scut / cut ( in your case ), a big mower, and then a used AG tractor. Believe me.. 2 tractors on a farming operation are bettert than 1.
Around here, you can buy old ag tractor from the 70's and 80's for 4000$ give or take. Things like ford 7XXX-8XXX, case 1XXX, MF 1XXX etc.. Even see deutz and big allis models in the 80-150 hp range with good used batwings in the 6000-9000 range in the trader mags.
Whatever you do.. the mower prices will shock you.. course.. if you are haying, that equipment will be a shock too, as you will wank a disc mower or at minimum, a sickle bar mower for the hay portion of the cut.
And bailers go for 'sky's the limit'!
Good luck with whatever you buy. Chinese tractors are $ per hp cheaper than most other domestic units except oldies....
Repairs are repairs. A new 80hp farm pro can break down on the first row just like an old 69' ford 8000... you pays yer money and takes yer chances! Preventitive maint. will go a long way to keep anything you buy happy and healthy. If you buy new.. find a good dealer... etc.
Soundguy