I have a diesel engine and it makes for fast acceleration with the 3,000 lb. plus camper load in the bed and it provides terrific engine braking on downgrades. Other than that it offers no advantages over a gas engine with the right gears. Mistake often made with gas powered trucks is not getting the lowest gears available which means the engine is operating a lot more of the time outside of its optimum power band.
Over 12,000 lbs. total load (bed and trailer) and the diesel is worth considering. A 3,000 lb. camper in the bed and towing a 4,000 lb. trailer and diesel is not the best choice.
The gain in MPG with diesel is offset by the higher cost of diesel fuel, the much higher cost of maintenance, and the extra $9,000 in purchase price. And if you do need repairs on a diesel engine you can expect to pay 4-10 times as much as with a gas engine.
With my diesel I have two batteries to replace and a fuel filter that has to be replaced every 10,000 miles, twice as much motor oil that needs to be replaced at half the drain interval with a gas engine.
There is seldom a logical reason for buying a diesel pickup but then logic little involved with most vehicles bought in the USA. That is why we have people driving Hummers and lifted trucks and pimped out Cadillac SUV's as they go to work or the grocery store or to pick up the kids from school.