since the diesel option is around 8k, not the 20k you stated, you can easily earn the premium back 10-15 times in the life of the vehicle in fuel savings. Don't convince yourself that all diesels are nearly $70,000 dollars. New 1 tons can be bought for 50k, and I'm not talking stripped models. Plenty of people pay that much for Ecoboost F150s, just to get half the mileage of my 1 ton diesel.
David & Lynn
2014 Coachmen Chaparral Signature 327 RLKS
2016 Ford F350 Lariat CC Dually