If you're looking to talk with friends going the same direction with a handheld, the best route is the FRS/GMRS style walkie talkies. Despite their huge range claims you might see a mile or so in real use in vehicles.
A true "CB" handheld really doesn't work in a vehicle, I remember trying it as a kid back during the CB boom and after with just no luck. Doesn't even matter if it is supposedly 4 or 5 watts, there's just not enough antenna for that frequency and the body of the vehicle presents too much shielding.
If you want to be able to listen and talk to other people on the open road like truckers and RV'ers, you're gonna need a permanently-installed CB antenna and a wired-in radio like a Cobra, etc. If a "rig" antenna seems unsightly, you can have some success with a shared antenna if those are still available, where you replace your usual radio antenna with one that is used by the vehicle radio and the CB. JCWhitney will likely carry something like that, among others.