High mileage vehicles are fine IF you plan on a rebuild (and can do it yourself) and add that to the price you pay for it and then be able to sell it and break even. Otherwise find lower mileage. Metal fatigues.
Always buy like you are going to sell.
I booked a 96 Chevy dually with 200,000 miles and came up $4995.
I then booked the same vehicle with 120,000 and only came up with $1500 difference. Doesn't look like a bargain to me.
But that is how I do it.
Remember...few people will buy a 200,000 mile vehicle regardless of new engine, trans, etc. So tough to sell when you want to move on. Basically you marry a high mileage vehicle when you buy it. That said....I drive a 99 Powerstroke with 233,000 miles...bought cheap due to miles and so far, so good.