Sherlock and Poirot have information from Don Juan:
http://londontales.ezblog.twwf.info/?p=228
The echo of either Moriarty or Morgan may be located here:
1472 Filbert St.
San Fransisco
California
There's another location of interest, one where the Cabal have had an "eventful" meeting:
Omni Hotel
251 S Olive St.
Los Angeles
And finally, Don Juan has suggested that the Phantom's Echo may be located in Central Park, New York
