All, thanks for your input. I have a couple of follow-up questions.
First, I should mention that my friend has the ability to buy the NAD products new at a very steep discount from an old friend in the business, so I am trying to stick with NAD amplification given the value that these components represent at this discount level.
Given that, I am wondering if there is a way to pair a second amplifier with the 320BEE to drive the pair of outside speakers. For instance, could the tape out portion of the tape loop circuit be used to feed a separate amp for this other "zone"? There would presumably be some sonic degradation due to the music signal passing through unnecessary circuitry, but we are talking about a ridiculously long run of low-grade speaker cable and a pair of mid-fi speakers in an outdoor situation so I really doubt that anyone could ever hear the difference...
Another thought would be to try to use the preamp out function on the 320BEE to feed a separate amp and these outdoor speakers. However, I suspect that the only way to get a preamp signal out of the unit is to break the link the amplifier section of the 320BEE integrated. Is this true?
Rich's idea of moving up to the C372 might well make the most sense, but, given that the cost of the C372 is more than double that of the 320BEE, I thought I would explore these other possibilities. The speaker switch box is probably the least expensive option, but I hesitate to put a switch in the path of the music signal for the main two-channel system.
Please give me your further thoughts on the above. And thanks for your help and your patience.