Hemi 6.4 Ram vs Ford 6.2 (gas)

Pulling 10K with a fifth wheel certainly makes a gas engine a viable option. If your looking to keep somewhat of a cap on expenses, the gas engines are cheaper to work on and not as particular as the new diesels are. The towing experience will not be as effortless and you wont likely pass many fuel stations. However when you factor in the cost of diesel verse gas in most places, the differences are not as far off as it might first appear. Something to remember when you complain about 7-8 mpg with the gasser verse the 10-11 with a diesel (towing). I pull half again as much with my gas HD and it works, I slay a few dinosaurs but I didn't spend the 8-9K for the Dmax either, that buys a lot gas. Lastly I just traded a '12 for a '15 with 60K on it (bought new) and it cost me .18 cents a mile in depreciation. It worked well enough for me that I bought another HD gas. Granted the HD gas truck is not my sole TV, but at 15K or less it works well.

I would say that I don't think problems with the new diesels are anywhere near epidemic, chances are better than not you would wont have any serious problems. However given your retired status, I can see why it is a risk you don't want to take.