I remember those days. Over the years, I remember a bluegrass-only station in Kentucky (Hopkinsville, I think). These stations carried farm reports, local obituaries, remote broadcasts at new business openings and they played actual vinyl records. You could tell they were records because the first 3 or 4 seconds of a cut of music was scratchy from being cued up by the DJs. Local news had stories about local fender-bender accidents, people under the weather, local folks leaving town to visit relatives, etc. National news was on the hour and usually came from the Mutual Broadcasting System.
My last DJ job in the early 80s used a mixture of media. We had 45s and LPs that the record companies sent out. We put some of our stuff on tape cartridge. We used NAB Type II cartridges for that. Those are the same as the old 4-track cartridges that disappeared from the streets when 8-tracks came out. We also had some music available on 10" tapes. That was backup. If a cartridge got messed up we could start the big tape. It was always cued and the pot on the board was always active. All we had to do was hit a button so dead air was minimal. And we were live with a few commercials, some sports scores, the weather, etc.
AND, it was AM stereo (Ta Dum!) The city was about 200K and I'll bet the three people who may have had an AM stereo radio were listening to rock music on our sister FM stereo station.