Carpeted floor, or bare? If it has carpeting and it uses a tack strip at the edges (and yo don't need to cross a doorway), you may be able to carefully lift the carpet at the base molding and tuck a 4 conductor cable in there. If you can't do that, some manufacturers make flat speaker wire and if you slit the carpet behind the equipment cabinet and behind each rear speaker location, you can slide a fish tape under the carpet and tie a string onto the end. Once you pull the string back to the source end, you can tie/tape the wire onto it and pull it to the speaker locations. Best to do this away from the general traffic areas.