I use
EdSets.com on my interstate. They're hardwired. I also have a Garmin Zumo. I can use my CB, radio, voice guidance, answer my cell phone using Bluetooth and talk to my passenger. I use the Garmin for my mp3 player (and xm radio.)
If you are interested I'd recommend calling EdSets and talk through your plan. They're very knowledgeable and pleasant to work with (when Ed's not out riding!)