Ya you are on the right path. Another lead digit won't kill you so going into another range isn't the worst thing. Frankly I would split it into 1XXX elementary, 2XXX middle school, 3XXX for high schools but whatever floats your boat. I assume you are netlinking or CCIS? Definitely be using ARS and F-Route tables. Should be fairly simple, you are looking the right way at it, NPL is everything. 911 isn't an issue for you with the SV9100, just get your ARS COS setup right (if netlinkled) otherwise with CCIS easy as pie.
