I've taken all of the tours listed. Enjoyed Stan Stephens more than the Lulu Belle, but did not have a bad trip with the Lu-Lu Belle. Major Marine/Kenai Fjords/26 Glacier tours were great. I can't remember which ones were connected to the railroad but (at least as of a few years ago) one could get the train from Anchorage to Seward, take the cruise, and return to Los Anchorage that night. Long day, but turnkey.
Stan Stephens passed away in 2013 (IIRC). Too bad. He (Brad Phillips was the pioneer) really helped create affordable and easy "tourism" in PWS.