Dragging in late with some opinions on CB stuff... Have you acquired one yet?
First of all, get the best antenna your budget can swing. A terrific CB with an average antenna is going to have just average performance. I've used mediocre antennas, average and very good. Wilson is my favorite and will stick with them for my future uses unless someone knocks them off the top of the mountain.
The complication with CBs in our Nissans is where to put the blasted thing. No room! The mini-sized ones can cram into the center console's cubby hole at the front although you will probably have to do some cutting if there are wires or antenna connections on the back side of the radio, which most have.
I personally don't like mounts on the dash or up high on the roof because I don't like heavy things that can fly around in a traffic accident.
What I do like are the all-in-one handsets like the Cobra 75 WX ST, which I have, or a similar model that Midland has. There's an ugly electronics box that has the transciever and has connections for antenna, power and aux. speaker that I have ziptied under the drivers seat. For the power, I wired in a 12 plug and plug it into the power receptical on the dash or in the console box. The heavy coiled cable for the hand held unit runs up from under the seat and I usually have the handheld in my lap or in a cup holder. When not using the CB, I just cram all the cords under the seat.
I'm using a Wilson 1000 metal antenna with a magnetic base. The antenna screws off the base and I store it in a closet when it's not in use on the Xterra Offroad. I have the lazy way of running the antenna cable. It goes under the floormat then under the back seat bottom. It comes up on the backside of the seat bottom and I just have it hanging on the side of the cargo area, below window level. When not in use, I cram the mag mount and cable in the side storage pocket at the back hatch. Because of the width of the magnet, I can only mount antenna at the very rear of the roof, not ideal but that's the way it goes! LOL! Yes, the mag mount can be knocked off by a limb that is within about 1.5 foot of the roof. The antenna has about a 6.5 foot mast and yes it whacks everything in creation but whips are tough and it's no big deal.
I also used the magnetic mount on my old Frontier truck simply by running the cable out the back door. Just kept the antenna stored behind the seat when not in use.
I've only seen these used on trucks a very few times but there is a real useful marine antenna mount that you can source through places like Boats US or West Marine. It can be roof rail mounted and has a rachet that will hold the antenna in the vertical position or lay it down horizontal.