Looking at a 2001 Limited tomorrow.
In my opinion, you have to see it. When you see it, you will know how it was treated.
Miles don't hurt vehicles, people do.
Also, I would find out when the major service was last done (timing belt, water pump, etc) as that is costly and due about every 80k to 100k miles.
Personally, I wouldn't buy any vehichle that was in bad shape. I'd rather pay more and get one that was treated well. When I was younger, I would buy the beaters that had been abused (for a low price), then fix them up, but I don't have time or energy to do that any more.
If you really like it, it couldn't hurt to offer him $6k and see what he says. Then if you really want it, be prepared to come up on your offer until he accepts.
When I bought mine, I knew when I saw it that it had been well taken care of, plus it was fully loaded with both the limited and sport package and everything worked and it had all the major services done recently (within 5k miles) and had new all terrain tires. The down side is it had 150k miles. He was asking $9k (blue book was around $10k) and said make me an offer. I said how about $6 and he said no way (dealer had offered him that in trade-in). He said his min price was $7.5k. I said I had to think about it, but he mentioned he had two other prospective buyers coming down the next day (Saturday). My wife and I left and discussed it and knew it would easily sell for $7.5 if not more as it was really in great shape. We both agreed we should get it, so I called him back and accepted his price. We paid and picked it up later that day. I get so many compliments on this 4Runner. Although it is is a 2000 year model, everyone who sees it thinks it is new. Since I bough it (last June),I have towed my boat with it, taken it up steep rocky trails to the top of 10k feet mountains (it loves to climb) and put 10k miles of my own on it. The oil is still as clean as when new. I absolutely love it.
Ray