Thanks, Dave.
I went and looked at it this morning. It hadn't been started in a couple of months, but even though it was right at freezing this morning, it instantly fired up and seemed to run great. I tested all of the controls, and drove it forward and back a little. 5 of the tires are fairly decent, and 1 is bald, but they all seem to hold air. The oil looks great (though significantly over full), and the coolant is clean and green.
I know that it hasn't moved for a long time because I drive by it every day. Even so, there were only a couple of drops of oil under it. As for the cutting edge, it is brand new, though I didn't inspect the attachment point. Overall, the machine seems to be in good mechanical condition.
The dude wants $7,000 for it.
It is bigger than I need, but small graders go for a fortune around here.