Tractor Advice Needed!

If the only thing you are going to do is cut grass, then I would go with the best at that job, Simplicity. Specifically, I would look at the Broadmoor 25/48 with the fabricated deck. With the bagger and Uncle Sam's share, you are looking in the neighborhood of $5500.00

You could also go with JD. Lots of people like green. Personally, I prefer the cut of orange, but to each their own. For you, I would start with the X310, it's well under your budget and gets good reviews. But if you are willing to spend what you stated, then you might want to look at the X324. The X324 has four wheel steering, 48" deck, and a slightly heavier gauge steel, along with a few more horses under the hood. With the bagger and taxes, it's about the same price as the Broadmoor.

If you truly have some serious hills, then a geared tranny isn't a bad idea. I had a house once with a back yard that rivaled any ski slope in New England. At the time I had a 1999 Craftsman with a 14.5HP Kohler Command engine, and a geared tranny, I don't recall the exact model. That LT climbed that hill once a week for 5.5 years without issue. Yes, every once in a while it would hit a slick spot that would spin the tires, (a bit nerve racking the first few times) but I would slowly back up and then climb the hill once again like nothing happened.