I would mount the radio in the trunk, then run a remote to the dash or ashtray location. audio into the aux jack under the arm rest. I wonder of the steering wheel kits people use for parrots can be adapted. It sounds like a parrot installtion in method and functionality.
I don't know jack about CB radio's but If I were to do this I'd solicit the advice from a CB enthusiast forum.
Good luck (east bound and down
