That's my 2 cents. Good luck. PS: I would avoid a diesel. A client of mine who services big rig diesels (and works on the consumer versions) told me never to buy a consumer size diesel truck. He said they are too expensive to repair and the cost of maintenance is way too high compared to gas and maintenance for a gas engine. The mileage is not that much better.
Everyone will have an opinion.. I say make your own. I have had multiple GM diesels both the 6.5: and Duramax, as well as my favorite 7.3L Power Stroke diesels. The 6.5s are not going to be powerhouses but they are far better then any gas engine GM offered in those year trucks. The Power-Stroke is a beast, I loved my F250 4x4, in 4L I think that truck could rip itself apart.
As far as consumer diesels they are built for a market and of course the durability is less then a HD or off road equipment, but so is the price.
For information as to up keep here is what I found.
Injectors for the PS diesel are about $425 each
Injector for the 6.5L are like $80 each
Injection pump for 6.5L is going to be around $1300 dressed and this is for a new pump not reman.
Turbos can be costly but often can be rebuilt for $500 or so if you find a good shop.
For the PS I kept a cam position sensor in the glove box, it was $100 and they tend to fail.
With any diesel you need to make sure fuel quality is the best you can provide. Change filters, avoid water, and run a GOOD diesel additive.. the additive might add $0.05 a gallon but pays off in the long run.
The benefit of a diesel pays off if you are going to use the truck as a work vehicle. For your daily driver car replacement of course the diesel is going to cost you more. But the benefits of the diesel come when you are working the vehicle. Towing a load will no longer be an issue unless your topping mountains with miles and miles of grade and you are maxing out the capacity of the truck.
I for own will own nothing else as a work vehicle. Put it this way the 7.3L Power-Stroke in a one Ton van or truck is rated to tow less because of the vehicle chassis. The same motor is used in International box and city trucks and some of those are rated to haul 15-20k LBS.
If you want HD diesel is the only way to go. If you want something you can work on then go gas, or I will offer free tech advise if you need it. I still hold an ADS certification and ran a fuel shop for a few years. I was the guy other "mechanics" brought vehicles to when they could not figure out power-train issues. I have worked on a bit of everything over the years, from HD off road to diesel lawn equipment.