Nobody can tell for sure. I know someone with '89 accord with 325,000 highway miles on it but he's the original owner and he keeps up with the maintenance. Only thing not original from his vehicle is the tranny, the exhaust pipe/muffler, the timing belt and of course the tires.
Make sure it's not all cosmetics, meaning the car recently detailed just to increase the resale value. Well maintained or not something is bound to fall apart sooner or later, which is common for any vehicle with such high mileage. In my opinion, shop around some more, look elsewhere for one with less/better mileage because it's really a gamble with this vehicle. Anyway, what's the asking price for it?