My thoughts, also having three boys and having had both gas and diesel. On the crew cab, be sure to get the big back seat, some dodges (not sure what years) had a smaller back seat and teenage boys will be tight.
Diesel vs Gas, I don't mind the gas on short and flat trips, but in the mountains or on long trips (we have traveled across the country) diesel is the way to go. Not just for the ease of towing, but also with a diesel, you can fill up at the truck stops where there is plenty of room to maneuver. Filling up at a gas station on the interstate trying to dodge all the cars is no fun.