Admin login for Linksys WCG200v2-CC router / gateway

While on vacation, I helped repay our host's hospitality by repairing her wireless setup. However, finding the admin login information for her peculiar gateway was a real bear, involving multiple phone calls to various companies. Google knows nothing of this, so I thought I'd post my research here for the sake of future frustrated web-searchers.

The WCG200v2-CC is a Comcast-branded, and therefore Comcast-mutated, variation on Linksys's WCG200 cable gateway. The username and password you use to access its admin interface are not those that the WCG200 normally uses.

The username is:
comcast

The password is
1234

I hope somebody finds this useful!