My previous post about selling the car was long and contorted, so I thought I should write something more to the point.
Simple: if you own one or more cars and and you want to travel for a long time, you will have to either find storage space for them or put them up for sale. We had three cars and chose to sell one and keep the other two. Angela's mother will take care of the Jeep and keep it at her place, and maybe drive it around once in a while. A friend of mine who owns a house with a three-space garage (these are hard to find!) will keep the BMW. Hopefully his offer is still valid - if I clean the junk in his garage he'll allow me to store the car at his place. I'm still considering selling the Jeep; Grand Cherokees year model 2000 seem to sell for between $7,000 and $10,000 on Craigslist, and the gas money I spend on this monster is about to make a hole in the wallet, but on the other hand I really wouldn't want to deal with the hassle of having to look for a car when we come back from the trip.
If you choose to keep your car at a storage facility you'll have to pay the big bucks. It's cheaper to lease an an open-air parking spot ($70+ per month); you may end up paying more than $200 for a secure indoors space. And good luck finding price quotes on the Internet - you'll find phone numbers, but most of those facilities don't have web sites. You will however find many sites that would give you "quotes" if you only give them your email and phone number. Ridiculous!
Once you decide to store a car, you should do it the right way and take all the necessary precautions to make sure it will run when you take it out of "hibernation". Here and here are a few tips on how to do this right.