What size garden are you going to work? How many horses? Do you need it to have a high bucket reach? Maybe need a mid-mount PTO for a belly attachment?
Those questions (and there are many more) need to be considered for sizing a tractor. I haven't dealt with the hydrostatic drive units very much, but would stay away from them for working ground, I think they would get hot from the fluid shearing vs the direct coupling of a gear/clutch transmission. But hydro drive are very nice for bucket work (cleaning pens) and other tasks that require frequent direction changes.
My parents had more but are down to 3 horses now, roping calves during the warmer months (~5), are on 5.5 acres, bushhog weeds, work fullsize arena.
My dad had a Kubota B7500 4wd (19HP PTO). 6x2 trans, super slow gears in the low range and low teens when topped out. Gear spacing was a little bit too far apart, for how we loaded it anyways, but that is just being nit picky. That was a working little machine! 4' bucket (frequent dumping required when cleaning pens), 2spd rear PTO and single speed mid PTO. It could barely pick up an 8' wide two row disc, but could drag it at near full depth through the clay dirt in New Harmony (Cedar City area) for working a horse arena (so the ground wasn't too tough to begin with). You had to go get a scoop of dirt before you went to work so that it had enough weight to steer and traction to pull. This was a disc that would make a 35Hp tractor get warm. We filled the rear tires about 2/3 full of water/antifreeze for ballast to the bucket. We rented a 5' tiller (smallest they had) and it spun that tiller in the hardpack of the horse pens. For its size, it did a lot of work. It did not reach high enough to easily load a hay rack on the roof of their horse trailer, but it did help. I think this unit was around $11k with 5' box blade and bushhog.
Put a few hundred hours on it before it was sold (had about 1100) and upgraded to a Kubota 4400 4wd (about 38HP PTO). 12x4 trans, low gear is still taller than the B7500 but not by much, wide out it will do about 18 (maybe more this thing flies). I'm sure one of these is well over your $5k mark, but the larger bucket and greater capacities make for fast work. He got it from somewhere in South Idaho.
We also have an older Ford 335 2wd (late 70's early 80's model diesel about 35HP) without the loader. It was the original for using that old 8' disc; I turned many acres with this tractor for pumpkins. I don't know how many thousand hours it has on it now, I remember my grandpa acquiring it in the mid 80's. It's worked ~40 acres since then (disc, bushhog/mowing, and other farming duties) and it still works like a champ. I wouldn't hesitate to purchase an older unit that has been maintained. It does weigh a little more than the L4400 Kubota.
Whatever you purchase, I think you MUST get a loader, and MUST get 4wd if it is a smaller tractor. Even with the liquid ballast on that B7500, no attachments on the 3-point required 4wd to keep it from spinning (even with dried horse poop), the loader is just so heavy compared to the rest of the tractor. The larger framed units seem to do better with only 2wd. That also makes me think about you moving the tractor, think of a weight that you can carry on a trailer you may already have...
I'm guessing an 18-25HP unit would work well for you. I don't have any leads on one at this time, but will keep an ear out. Hope this helps.
