Step 5: TV and Sound System
I had a Nuvo Grand Concerto whole house audio system already in the main house and had an extra zone so I just needed to run speaker and Cat 5 to wire the Playhouse for sound. The Nuvo Grand Conerto is very nice, they run $3,500 & up retail but you can pick one up off eBay for $2K.
I picked up the in-wall ceiling speakers from www.hometech.com that weren't too expensive ($80) and sound pretty good. The speaker grills are paintable to blend in with the ceiling.