The thing to keep in mind about CB (and any radio) is that the performance will only be as good as the antenna. Just as the same applies to Hi-Fi and loudspeakers. The best source/preamp/amp is worthless behind a crappy set of speakers.

The maximum legal output of any CB (not using SSB) is four watts. And pretty much any CB you buy today is going to be four watts, whether handheld or a base station. So a good antenna is what is going to make the difference. They make magnetic mount antennas that hold really tight. You could place it on your hood or somewhere else out of the way if you think that would work at all.

It is also important to minimize standing wave reflections (SWR) so that you get the best performance possible from your antenna. You'll need an SWR meter to measure this. You adjust the location of the antenna and the length to minimize SWR.

My personal experience is that a range of 4 miles or more is reasonable in flat terrain with a good antenna. I don't have experience in mountainous or very hilly areas, but obviously that will cut down on the range.

Also, the range you will get is dependent on what kind of propagation or "skip" you are encountering. When sunspots are high and signals are bouncing wildly off the ionosphere, you are going to have to turn the squelch way up to cut down on the chatter from people hundreds of miles away. This of course cuts down on the effective range of the radio. I remember times when there was a lot of skip that I had a hard time communicating with someone less than 1 mile from me using a radio that put out more than 4 watts.

So in summary, spend the money on an antenna and set it up correctly. The radio itself is secondary and not very important.