I had the same thoughts as Pete.
You are looking for a lot of HP for your acreage.
Stall cleaning I'd expect to be a very tricky operation with a tractor. Seems like skid-steers are purpose built for such a task, interesting point on stall cleaning. Any horse place I've been at with my daughter has a farm hand to shovels out the stall and then a tractor with loader for cleaning out the catch basin the dump all the shovelings into, seems tough to get away from wheelbarrow work?
Anyway, I have a 30HP tractor, PTO around 25HP or so. I run a 5 foot tiller no problem all day long. 3-4 acres just doesn't seem like that much ground to cover for the frequency with which you till.
I live in rock country and I've not run into anything I can dig up and move (well maybe a couple of boulders, which ultimately required a 25K excavator).
I'm certain I can run a decent sized bushhog and clean 3 acres in fairly short order. Finish mowing the same.
Anything 15-20 acres and bailing and the like and I'd likely think very differently.
Would be great if there are similar farms in your area and see what they are running.
Anyway, good luck with what ever.
Sincerely,
Joel