Here's the deal: I got it with a little over 200,000 miles on it, it's been extremely reliable. It's the 7.4/454, not the 350. Last year, it overheated pretty bad, out on the interstate. I put a new radiator in it, and a new thermostat. It ran ok on short hops, all this past summer, but I wouldn't take it on any trips until you tear into it to see how much engine damage there is. No water in the oil that I've been able to see on the dipstick. I haven't had the oil pan off.
The good: The interior isn't bad, for such high miles. The tires still have a lot of wear left. The body is in good shape, no major rust. The transmission shifts fine, though first gear shifts a little hard; it still tows great. The battery is fine, and the radiator probably has 500 miles on it. I paid around $450 for that.
The bad: Aside from not knowing how much engine damage there is, from overheating, it has the usual door handle issues for this GM era. The driver's door won't open from the inside, you have to roll down the window. (Power window works fine). It needs new rear shocks, so the rear suspension feels pretty mushy.
So what you're getting is: A high mileage, heavy duty suburban that may or may not have serious engine damage, and which has has been well taken care of, but has high mileage.
I've listed for a $1000, the radiator is worth a third of that. I'll consider offers, though. If you want the large rack that's on the roof, I'll let that go for an extra $150, it's 4 x 8. The rear facing seat that's in the back obviously isn't stock. If you want it, take it, if not, it's easy to pull out.