In User Documentation -> "Using Failsafe Mode to reset a forgotten password", AD5OO mentions not getting the procedure to work with a v2 router.  I'm happy to report it did with one of my v2s.

I use the same password for the six WRT54G/GL routers I have.  After initial configuration and setting up as a host for a Addonics NAS 4.0 adapter, one of the v2 routers worked fine.  Later, when attempting to log in, it wouldn't take the password.  I performed a 30-30-30 on it and it came back up as NOCALL-40-31-219, but would not take the default or previous user-defined password.  I followed the Failsafe mode instructions and setpasswd to the one I use. I was then able to set up the router as KJ4AJP-MESH6. 

Oddly, the 30-30-30 did not remove/reset the port forwarding values for the NAS, they remained and had to be deleted since I had moved the NAS to MESH1.

Another oddity is that the router is displayed on the Mesh Status pages of the other routers as KJ4AJP-MESH6/NOCALL-40-31-219.  This has been going on for a day, hopefully it's just "memory effect" and the /NOCALL portion will eventually go away.

Other than that (and the antenna port question) MESH6 is doing fine, it can access the NAS on MESH1 and I'm getting the internet service from MESH5.  Now I'm waiting on USPS to deliver two IP cameras and a USB webcam...