This is how the sign outside the RKO General studios and office building at 21 Brookline Avenue in Boston appeared at the time of the format change in 1967.  It was probably as popular as the Cities Service sign outside of Fenway Park that could be seen from almost anywhere within the park.

Note the "Yankee Network." That was a network of about 33 New England radio stations to which the former WNAC-AM provided New England-area news as entire newscasts, opening sounder and all.
The Yankee Network was disbanded at the time of the format change. While many of its anchors continued on into WRKO, some moved elsewhere after a short time at the Big 68.  For example, Roger Skibines went to be on the air at WOR, New York.  Here's a quick aircheck of "Skibby," as his colleagues called him. 

Palmer Payne (also a WNAC-TV anchor) moved on to WINS and then to WCBS, NewsRadio 88, New York.

When he left radio, Palmer became involved in politics in his home state of Maine.  At one time, he was a Selectman for the town of Boothbay Harbor.