I'm looking at a 2009 Chevrolet Silverado 3500 HD, 4WD, 6.6L Duramax Turbo Diesel with a "reported" 172K Highway Miles on it.

It was fleet maintained and while it looks good, what kind of future miles can I hope to get from this truck if I continue to maintain it?

I want to put a camper on back and drive it around the country.

Any particular issues I should look out for?
From what I read, the 6.6 engine is pretty good. True?