Against my better judgment...
Like other posters have said, there are lots of places on the West where diesel can be difficult to find.
My old boss would specify gas when buying our work trucks just because that could happen to us just from work situations. Come dragging back into some tiny town and no diesel.
Now, I've had the same issue with gas. Top off my F-250 in the last town, drive in to the work site, maybe 120 miles of transit while we are there, and hope I get back to town without getting into my jerry can. In the winter, I carried a second jerry can because I'd be sure to need the first.
Fuel issues can be always mitigated, if you really feel you have to have either fuel for whatever reason, a tiny bit of planning should ensure you have plenty.
Now, when I left Bend last week, gas and diesel were each just over $3.00 a gallon. A pretty good deal for diesel. In Boise today, gas is $2.58 and diesel is $3.14. Does your diesel get 20% better mileage?
In my case, yes. My 7.3L Econoline get 16mpg. Any gas motor of similar capability would get just over half that .
Maybe. If mine were 2WD, I'd get even better. I can easily break 500 miles before I would need to use my cans.
And it will survive the Apocalypse.
BUT, Binky was something unexpected and I could never afford the premiums if I had to pay retail for it.
I'm a big fan of vans. My Astro can get all kinds of stupid places, tow 5500 lbs, comfortably carry 5 and get decent mileage. All with just a mild lift, a skid plate and bigger tires. But really it's a rolling, all-weather tent for 2. I was researching a bus (with one of those DD 8V72 engines the military still uses a variant of) and found Binky.
I like the suggestion of a Transit 4wd, whether factory or aftermarket, gas, EcoBoost. The new 2.8l diesel Express is supposed to be a real hauler. Vans are versatile people/stuff haulers/grocery getters. Minor modifications make them capable 'overlanders'. Take everyone along and tow the Jeep to the trailhead.
Take a look at some of the rigs on the van forum.
John
PS, I really want a Colorado ZR2 w/ 2.8 Duramax!