Just wanted to get some feedback on this. Now that Unmanaged room types are a reality, i took some time to get to know the UpdateEntArea code a little more deeply. I now know of a good reliable way to lock autogenerated scenarios so that you can make changes to them and have them survive a router reload.
Please see trac ticket #93 http://svn.linuxmce.org/trac.cgi/ticket/93
and let me know if anyone disagrees with this approach or has anything else to add before I get moving on this.