Replacing the injectors on a diesel engine will cost more than a complete rebuild of a gas engine. Diesel fuel is very dirty and diesel injectors do not last anywhere near as long as the ones in gas engines.
Diesel costs more at the pumps, is harder to find while traveling, costs twice as much to maintain and 2-3 times as much to repair.
Where a diesel helps is when you need a great deal of torque for very heavy vehicle and tow load combinations. Get upwards of a gross combined weight of 20,000 lbs. and the diesel is the way to go.
The one exception is the Sprinter Class B motorhomes with the 5 cylinder Mercedes diesel engine which average over 22 MPG if not towing.