I was surprised at how many episodes Bryna Rayburne was in in the 50's and then we found her in loads in the RMT's as well. Greg Bell said she was in other OTR revivals as well. 

And, of course, Larry Haynes not only was around in the 40's and 50's and in the RMT, but was a talking book reader way back when, along with Ralph Bell who I always love hearing in an OTR program from whenever he shows up. He just made the perfect bad guy.