My wife and I have a commercial van we keep all our survival gear in. We live in the San Francisco Bay Area, and we expect a major earthquake followed by an even more major fire (as all the gas mains and water mains will be broken by the quake).

Jalopnik has a photo essay of some survival vehicles which are very impressive:
http://jalopnik.com/360213/the-ten-best-post+apocalyptic-survival-vehicles

I'm not sure about getting fuel, though, after a quake wipes out all the electricity. And the mileage doesn't look too good on some of these bad boys.

That's why they make and sell big aux tanks.

That's the Hall of Fame of BOVs. None of them gas sippers. I'd love to have a Sportsmobile 4x4.

Scary to try to get out of San Francisco in that situation. Ditto on the auxiliary tank. And how about gas cans on the roof, locked, and a couple bikes on the back?

I saw a sportmobile 4x4 last weekend. All dolled up for bizness. Very cool . Honestly right now I'm looking for am international scout or bronco, pre 1977. No extra power options, dependable. If icould find a military cucv (6.5 Liter diesel K-5 blazer) I'd grab it.

Met a guy with a Sportsmobile while on a too short holiday in Zion National Park a few weeks ago. A bit pricey but the coolness factor is incalculable.

With a 40 gallon tank and the diesel engine, you're looking at least 700-800 mile range, more if you carry a few cans of extra fuel.

I started with a 4x4 extended cab truck. Cab is big enough to carry my family. Replaced the stock passenger rated tires with off road capable truck tires with a matching spare. Fill every open place with tools, spare parts and supplies. Under hood second battery, can jump start myself if needed.
Had a cap on the back with sleeping bags and camping gear and a tent but as my family went from 2 to 4 that was a getting kind of small. Now have a popup truck camper, beds, closet, pantry, refrigerator, stove, furnace all ready to go.

I would think that instead of big with a gas guzzling engine you might go for something more like the old Willys Jeep. Fairly small, compact, with a small, simple, fuel efficient engine that carries a lot of weight for its size through gearing. The old Jeep only had, depending on year, about between 20 and 60HP worth of gasoline engine with the majority or wartime production having 60HP. At capacity, considerably more than 3/4 ton, on a flat road it would only do 40 mph but, as the saying goes, it could climb a tree. Small, a tight turn radius, and narrow helps when you need to drive around obstacles and on sidewalks.

I would go for a small 1/2 ton diesel truck outfitted with a 3/4 ton rear axle. Diesel saves a lot of complication by eliminating the ignition system and diesels have become much lighter than they used to be. Something with gearing making it just capable of interstate highway speeds. Most highways are legal down to 45 or 50 mph around here but I would want at least 60 mph at half load so I can take it out on the highway before any disaster.

In an emergency the 'need for speed' is limited. After an earthquake you don't want to go flying off a broken overpass and keeping your speed at around 25 mph should increase your mileage considerably. Which further saves weight and trouble. Something with a frame. A lightweight one ton winch, rigging straps and a couple of snatch blocks should allow you to shift anything you need to.

A small trailer would add weight and save wear on the suspension. It would also allow you to bring a larger load but leave a majority behind so you can scoot up ahead and check things out. A small teardrop trailer would give you a place to sleep and keep your gear dry and relatively secure.

My father had a willys jeep, the old carburated engine was small but not efficient. You can't buy a 1/2 ton diesel truck, you have to get a 3/4 ton to get a diesel.
The current full size 4x4's all get over 20mpg (well the big three anyway, the japanese brands cant seem to figure out economy). Most of the mid sized v6 trucks/suv's all get about the same fuel economy, they certainly are not "gas guzzelers".

Be nice if one of the (not so) big three would market a 2.5-3 liter diesel for their small trucks such as the Ford Ranger. It would get 30+ mpg and with the standard 20 gal tanks -- 700+ miles, with a payload.

I think they are right that no one would buy it. The cost between a smaller truck and full size truck isn't that much anymore,if you ad the cost of a diesel to a smaller truck then its cost will be more than a full size. Thats one of the reasons I moved to a full size myself, the initial cost was about the same, economy was the same and to have room for the kids in the smaller truck I'd have to have the quad cab with the 4.5' bed where a full size I could get an extended cab with a 6' bed since the back of the extended cab was big enough to fit the child seats.