For you guys thinking about getting a CB. If all you are going to use it for is off road communications a couple times a year, buy a cheap one. You can get these at numerous places and pay from $35 on up. I bought one from the Sportsman's Guide online for about $50 in that it had NOAA weather channels on it. Anyway, once you get a radio, go to Radio Shack and buy a cigarette lighter plug. Splice the wires from the radio onto the plug and you are good to go. While at radio shack pick up a cheap magnetic mount antenna and you are ready to go.
A couple of other choices include, simply buying one of those emergency type CBs. They usually come in a kit with a radio that already plugs into a cigarette lighter, and a magnetic antenna. These work pretty well and are pretty cheap, usually less than $50.
Another choice is a hand held. These run off of batteries, but usually come with a cigarette plug. They have a "rubber duckie" antenna, but some have a jack on them for an exterior antenna. Or you can usually buy an outside antenna for them as an option. You can find like new refurbished ones on Ebay for less than $20. These are pretty good radios and I think some even include NOAA weather channels on them.