Posted By: 
Bill CornellTed -
Very plausible analysis, as usual.  I do think that T204's were issued regionally - 20 years ago, many more of them would show up in N.E. than elsewhere.  The Worcester/Boston connection seems obvious, given the player biographies we have now.  
My purely speculative guess is that the set was intended to have more than 121 players, which is a strange number: sheets of 11x11 (= 121) seems unlikely.  This may account for why Philadelphia has only Bransfield and why Pittsburgh was also completely omitted.  
Washington was almost completely shut out from all E sets, with the exception of Schaefer.  Perhaps it's because they stunk...
Bill