RTI makes a waterproof remote and havae for about 6 years but I don't know who sells them. For any system that you can't see, use RF- it's a lot more reliable. If you want to make setup of the second zones easier and more fault tolerant, use a separate AV receiver if you want to use digital audio inputs (most stereo receivers don't have optical or digital coax inputs). That way, you can use the tuner outside when the main one is using the tuner inside. If you want to listen to XM/Sirius, get a deceiver that has an XM input. This way, the two systems are controlled separately, although they can share the sources if you want.