Okay so the clarification is as follows: 

/rc/bin/cpurc.local only pertains to the intial system that
booted such as the first system which is CPU/Auth. 
However you don't really need that file. Its' just a diff of
/rc/bin/cpurc. So really its also optional

The /cfg/$sysname/cpurc is also optional and no cpurc.local
should exist in that directory. It only pertains to machines
that will boot off the initial server (CPU/Auth). And the
file should be a minimum file of things needed such as
auth/secstore or maybe auth/httpd if you wanted to dedicated
the new cpu to just service httpd as a service right?

As far as a mount point to copy data back and forth. No mount
point exists you still have to mout it directly using commands such as having a listener on the server

server% aux/listen1 -tv tcp!*!9999 /bin/exportfs -R -r /

client% srv tcp!192.168.1.172!9999 servrer /n/server

something like that right?