Fred,
I'm using a Cobra 75 WXST that I got from
www.walcottcb.com There service was good; they are selling them now for $109.95. The nice thing about this model is that all the controls are in the handset part, so it takes up very little space. You mount a small box someplace maybe under the dash or in the center console, then just run the handset cord out to where ever you want to hang it.
About the only not so great part is that means the speaker is also in the handset, so it is not real big or loud. You can attach an external speaker, if you can find a place for it.
I think that they all have the same output power, so I see no reason to take up already limited cabin space with a larger unit, especially if it's just for trail communication.
I've been real happy with mine, and I think several others here have the same one as well.