The "Cheap" way....believe it or not....would total no more than 300 bucks for 2 receivers...1 stereo (For the whole house distribution) and the other full 5.1 With a bit of wiring you could keep the speakers in your viewing room for the 5.1 system as the rear speakers. Since you'd be adding a pair of fronts, a center and a sub....your front speakers would now be the stereo music listening speakers for that room. No sense using the in-walls for that purpose anymore. The distribution system needs to be done right to prevent damage to the stereo receiver. Since you already have volume controls in each room, you might already have everything you need for that system. I can't be sure unless I knew what kind of volume controls they were, or the impedance of the system at the supply terminals to the system. The advantage of this 2-receiver system is that while someone is watching a DVD in 5.1 surround in the viewing room. Another person can be listening to whatever else they want in another room. Add in a IR/RF remote to that receiver and you've got wireless control. Keep in mind that for $300, you're not getting top of the line receivers, but you're getting adequate for what it sounds like your parents need/want.