Is your goal to be able to travel off-road and through extreme weather conditions, or to simply fit your family and gear for evacuation on-pavement?

If its the latter, an AWD minivan with good tires would be your best choice. But if its the former, I suggest you rethink the idea of using something like a CRV, Element, RAV4 or Subaru. I don't have anything against those small crossovers, I think they do an excellent job of dealing with most bad weather conditions and even some light-duty off-road situations. But if traffic has reached the point where getting to safety means leaving pavement or dealing with deep snow and/or debris, I would not want to bet my life on what's essentially a modern-day station wagon with all wheel drive. If a tractor trailer can't get through the snow or water, what makes you think your station wagon will make it? But of all the choices, the Subaru Outback would be my #1 pick: at least it has decent ground clearance and somewhat capable AWD.

Remember that if you're stuck in traffic and considering leaving the blacktop to get to safety, hundreds of others will too. Any trails easily driven by a CUV or other less-capable vehicle will likely get clogged and then blocked by other stuck drivers, if they aren't already blocked-off my officials. The shoulders and medians of highways will be clogged with people who got stuck trying to get around other stuck vehicles. I've seen this happen more than once. IMO, you need a vehicle that is easily maneuverable as well as able to safely drive through moderate to moderate-plus off-road terrain, that also makes sense as an additional vehicle for camping, hunting, the beach and other outdoors activities.

I happen to agree that an old Jeep Cherokee seems to be the ideal bug-out vehicle. No, it won't get 30MPG, but around 20-22 in stock configuration isn't that far off a Subaru and offers a great amount of capability. You can pick up a good condition pre-1999 Cherokee (XJ) with around 150K miles for under $3,000, spend $1-2k in maintenance and repairs, then put another 100K miles on it with little concern for any major drive train issues. The $25K you save versus a new CUV will pay for a lot of repairs, spare parts, upgrades and gas.

Well-built and well-maintained XJ's, upgraded for serious off-road capabilities but still with good on-road manners and decent fuel economy, can be found for $5,000 to $10,000. You can also upgrade the Cherokee yourself, spending between $3,000 and $5,000 in used but still reliable parts (available from members on any of the dozens of Jeep-related websites and local clubs), and make something that can go practically any other vehicle can travel, and do so with your entire family and weeks' worth of gear and supplies. I suggest building rather than buying because you not only get exactly what you want for both quality and function, but you also learn how to maintain and repair the vehicle, and what spare parts you need to keep handy.

If you stick with 1998 or earlier years you eliminate some of the reliability and component selection problems that plagued the '99 and later years (though with more than 100K miles, these problems should already have occurred and been fixed). The only major issues of concern would be improper maintenance and repairs, rust, and models with the Dana 35 rear axle (infamous because of its weakness and because when it breaks it is a PITA to repair). But used parts in good condition are plentiful and cheap: bare engines for $200-300, drop-in engines for 400-600, transmissions for $150-300, transfer cases for $75-150, computer modules for $50-100, complete wiring harnesses for $100, aftermarket parts for 30-50% of their cost new.

An XJ is not a bad daily driver or commuter vehicle, either. Of course if you add a lift, large tires and heavy armor for off-roading you will affect its road manners and MPG. But small changes can make a big difference in off-road capability while not greatly affecting comfort or economy.

There are some other older SUV's that are also worth considering, though the availability of aftermarket parts -- used or new -- can be a problem: Nissan Pathfinder, Ford Explorer, GMC Jimmy, Toyota 4Runner, Toyota Land Cruiser, Land Rover Discovery or Range Rover.

I'd also suggest the new Jeep Wrangler 4-door. I own a 2010 model, and know many people who own 2007 through 2013 models. The newer engine is nice, but there's no persistent reliability issues with the 07-11 motor, other than it doesn't have as much pep on the highway. In fact, it seems there are a lot more reliability issues with the new motor than the old. But the JK, particularly in 4-door trim, is a bigger vehicle on the outside than an XJ, while being smaller on the inside. It is also less nimble on-pavement, has less cargo space (discounting height differences), and is not as comfortable to drive on-pavement (it is a Jeep). Finally, a 4-Door Rubicon edition with all the off-road options offered by Jeep will cost over $40K new, and you'll be lucky to get 18MPG stock.

The Toyota FJ Cruiser might also be worth looking at, but passenger and cargo space isn't equal to the others mentioned above.