If you decide to get a CB radio for your RV be very careful to get the right antenna. If you mount it on the fibreglass shell you need a no ground plane (NGP) antenna. This is very important otherwise you can buy the best CB radio going and it won't work properly. I highly recommend the Firestik No Ground Plane antenna. If you go to Firestik Antenna Company Home Page
they explain why RV CB antennas are different than antennas that are mounted on the steel of a truck or car.
I mounted a Model FG2-DD-W on the roof of my RV and I get great reception.
If you are concerned it will stick up too much you can get one that mounts on the side of the RV with part of the antenna sticking up past the roof line. The more it can go past the roof line, the better the reception.
I agree with others that language used on the Channel 19 is a little "rough" to say the least, but having the CB has saved us from unanticipated road closures to tornado level winds ahead. It is also entertaining on long drives.