Seeing a vehicle with between 2 and 300,000 miles these days is quit common, no matter the brand.
Transmission and front steering parts will be what gives in the most trouble when the miles start to add up.
I haven't had a 1/2 ton in the last 27-28 years. Just have always bought 3/4 ton's or 1 ton's.
I like Mobile 1 15,000 mile Syn. oil for gas engines and Mobile Delvac 1300 for my diesel's.
Leather vs cloth....the only down fall's of leather are cold to sit on in the winter and not the best when a person is soak and wet. Either way, it wouldn't be a deal decider for me either way.
Ford IMO, has always had auto transmission issues when the miles add up Their E4 OD had a reputation for failure in fleet service vehicles. A guy I knew that had a fleet of step cube vans in service kept two spare transmissions on hand at all times.
In the diesel engine category. Fords new in house built motor has yet to prove itself. The 6.0 liter had plenty of issues, even though it was still built by IH. The Durmax had most it's issues addressed over it's time. The Cummins has no equal, it rules in longevity and fuel milage. The Ford built motor had some teething issues. #1 was engine trouble with long term idling. A friend sell's ambulances and they had trouble even getting the 6.7's at one time because of this issue and Ford halting shipment until they could remedy the problem. I still think it has promise. Some are getting real good fuel mileage with the 6.7
As far as gas engine options. Not much of a V6 person. It's a matter of physics. You simply can't make a V6 perform as a V8 in the gas engine application. All brands have great V8 options that will service you for a long time pretty much service free other then oil and filter changes.
I'm loyal to no brand and have had good luck with them all. That just kills some. They are so set in their ways. You have to drive a certain brand, be it truck, car, boat, ATV, motorcycle, vote a certain way, shoot a certain brand gun, Etc, Etc, Etc...I think in the end. They just like to fight and argue.
Buy whatever trips your trigger and enjoy it. That's all that counts. It should have no baring on acceptance by your piers.