I sold my 2002 Chevy 2500 HD with the Duramax diesel when it had right at 300000 miles 2  years ago. Been regretting it ever since but it was about to need new injectors again which would have cost close to $3500 and I didn't have it. And I sold it when Duramax prices were still crazy high. Now they are just high.
I still have a 2008 GMC Duramax with 210000 miles that I won't be afraid to take across the country. But I would not have been afraid to take the 2002 across the country either and it would have drove better and more comfortable than the 2008. lol

Wife's 2011 Chevy Suburban had 220000 miles on it when we traded it for a Yukon with only 80000 miles on it. It was starting to have some small issues and the engine was starting to use a bit more oil than what I liked. Other than that it was immaculate still.