That's exactly what we do. Our Bose Wave sits on the dash and you have a remove to operate it. Sounds better than the dash radio anyway. If it's cd's that the kids want to listen to while on the road, I use the Aux jack and run it through the dash radio and put it on the back speakers. It goes into the house with us when we are at home.
DW and I sing with the praise band at our church so lots of times when on the road we are singing away with instrumental cd's on our Bose.
We love our Bose. Good quality stuff. We even use their ear buds for when we sing at church.
Oh almost forgot. Check out their outlet stores. A bit of a discount.