Isn't the "diesels are more reliable" thing an urban myth anyway? Back in the old days diesels were very simple, very noisy, and very dirty. Now they're quieter and cleaner, but the cost is more complexity (DEF and such), greater cost initially and as I understand it, greater maintenance cost. On top of all that, you're paying $0.25 - .50 more per gallon for fuel.

For that matter, "reliability" and "longevity" of ALL vehicles is much greater now than it was 25 or 30 years ago. I know there was a time when diesel engines lasted longer than gas engines but I think the modern gas engines have closed that gap so if "reliability" is the only reason you're looking at a diesel I'd check out gas engined trucks - they're likely as "reliable" as you need a truck to be.

If you need the stump-pulling torque that a diesel offers I could understand, but it sounds like you don't. Do you even need a 3/4 ton? If MPG is important I'd consider a half ton. BTW the F-150 Ecoboost 3.5 V6 has something like 435 lb/ft of torque.