I need some advice on buying a new mower. I have about 4 acres of yard to mow. I currently use a JD 750 tractor with a 60" finish mower. My tractor is in mint condition and extremely low hours for its age. I hate to put a ton of hours on it. And it mows great for flat areas, but sucks for trim work and uneven ground. I had a very small Dixon that I used for trim work, but it bit the dust last summer. I want to replace it with a decent Grasshopper that is big enough to mow the whole yard and will be faster than my tractor. I found what looks like a very nice used 1997 model 725 with 1775 hours. Seller says its a one owner and never used commercially. Says its always been garaged and it does look very clean. No rust at all. Seat looks brand new. Seller says it burns no oil and that he changes the oil every 90hrs. Says it has a new alternator, water pump, belts, and hoses put on last year. Tires look about half worn. The seller wants $3500, but I have no idea if that's a decent price or if there are some concerns with this model. Any help and advice would be appreciated.