If you have a line on a 7.3 diesel, they are a great power plant. You can plan to get + 200K out of a 7.3. My experience is that anything on the road will need some sort of suspension work and other minor repairs when near 100K miles. The automakers don't make everything in a van, truck, or car to last 200K mi.. There are expendable parts even in a new vehicle.
Lately, I've been looking at retired ambulances, either with body or cab on chassis. Most all are fleet maintained to a high degree, come with 600 A alternators and with body, have an RV style ready-to-roll. You may wish to explore that route if you're looking for a well maintained vehicle.
