I would recommend a Firestik II or FireFly, "No-Ground Plane" antenna. See: FireStik Company
Can't give you the direct page, since they use Frames on their website. The FireFly is also a top loaded antenna, where the signal radiates from the top of the antenna rather than the middle. All of their antennas allow tuning from the top of the antenna.
There is no such thing as a "no-tune required" CB antenna. If you see one advertised as such, avoid it.
Mount it on the drivers side as near to the top as you can. Use any cabinetry to hide where it penetrations the side wall. Be sure to use a quality caulk. They also offer a roof mount, but the side mount is easier to seal.
Be sure to get the longest whip (antenna) that is reasonable for your application. The full wave length of CB antenna 36 feet, even a quarter wave is 9 feet. Thus a 4 foot whip is a comprimise.
Some people claim that dual CB antennas are better than single. The real difference is the shape of the radiation pattern. On a single antenna the radiation pattern is circular, with two antennas there are pronounced lobes perpendicular to the antennas and reduced radiation in-line. When the two antennas are mounted on the sides of a truck or motorhome this means there is better transmission and reception to the front and rear of the vehicle, but reduced sensitivity to the sides.
I am not affliated with FireStik in any way, but have used their products on several vehicles and have lots of Off-road friends that use them a lot.