WXYZ am 1270 with dj's like Lee Allan , Dave Prince ,any body remember Chicken Man on xyz? WABX in late 60's and other early "progressive" rock stations in the late 60's early 70's when they would play everything from Rock to Jazz to blues the only thing that came close to that was when WDET used to play music.
WXYT when Mark Scott and David Newman were there.
Definitely WABX, the original WRIF and WWWW....
You are spot on about the progressive thing. You'd hear Joni Mitchell and Iron Butterfly, back to back..... then, there's the
famous Janis Jophlin interview where the S word made it on the air.