yeah, my E350 blocks more air than an Excursion or Expy and I got 21mpg going to Kelley's Island and back 2 weekends ago. We had 2 12' kayaks on the roof with 2 bikes laying sideways on top of them and 6 more bikes on the back plus were pulling a pop-up camper behind those. And we had 10 people aboard, all their gear and groceries, and it was pouring down rain just about the whole way there and back.
Diesel is more than gas. Diesel efficiency is a lot, lot more than gas efficiency. With a 5.4 in my van, would I get 15, or 14 or 12mpg with that load? How about 21mpg? That's what we get in my wife's Honda Pilot--with no external loads.
I used to want a diesel Excursion, but the awesome internal load capacity of a 15-pax van talked me out of it. I own a schoolbus camper, which is what we usually take on vacation when we aren't renting cabins or condos, and it gets 5.4 type mpg. But the 15-pax van, when you just need to haul people and gear, is awesome. It's 2 feet shorter than my crewcab pickup, and the wheelbase is almost 3' shorter, so it is much more maneuverable in town. The interior area is like a warehouse. We usually pull out either the first bench or the third bench.
On a long, long trip with just my wife and myself, pulling out the third bench and stacking and strapping all the cargo in the gap back there leaves the long rear seat open for the the off-duty driver to sleep on. We put everything in laundry bags, with each kid having their own duffel for their stuff, and we stack it to the ceiling and strap it down to the seat mounts. When we have another family with us and plenty of drivers, we remove the first bench and strap everything there.
I put in a big flip-down TV and a RAM laptop stand in the front. With a bunch of infared head phones, everyone that's awake can watch movies without the driver noticing and being distracted. The movies can also be played over the van's sound system--Rockford Fosgates all around.
Nothing beats a 15-pax van. We had 9-pax Suburbans before, same interior space as an Excursion and more than an Expy, nothing at all in comparison to a van. The interior height is much greater in a van and the interior length is very much greater. Hell, our Honda Pilot has 3 rows of seats and holds 8 people, but there is very little room left for gear.
My bug-out preference is a school bus. Second, a 15-pax van.
Nevermind 4wd. A van with a winch and a locking rear axle with mud tires will go just as far. Eventually, when you run out of roads, you'll need a winch. A van is very heavy on the drive axle and a lot better in 2wd than a pickup. It might be worth converting a van to 4wd, but I don't think so.
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