I think there may be the stray station with some version of the 'beautiful music' format - not really contemporary instrumentals or a new age variation on 'smooth jazz' - in Texas and Florida, and mayne one in Tennessee somewhere. For conservative retirees, I suppose.
My family moved from Detroit to Toledo in 1968. I was a pre-teenybopper who dialed around AM and FM a lot and recall BM on the following outlets:
WSPD-FM Toledo 101.5, which became WLQR when Susquehanna took it over and refined the format. I used to hang out in their studio when a buddy did his airshift on the station. They had the usual large tapes filled with instrumental versions of popular songs, plus a few other instrumentals that actually worked as something other than "cover songs." And a few soft vocals, but very little of what would make it into the Music of Your Life" format. Local announcers all the time, with short newscasts each hour. WLQR (I was told the call letters were supposed to suggest "liquor") probably dominated the market back then, since they did a better job with the format than the others without live announcers.
WMHE-FM 92.5 Toledo was still in mono with actual "muzak" on the air, since the licensee held the local francise for that dreck. But they did eventually go stereo at night for Toledo Symphony broadcasts, which, strangely, cleared up their not-yet-50kw signal, as opposed to the severe multipath or "twisted" clarity on their mono signal, despite the area's flat terrain. I recall WLQR later picked up the TSO concerts on Sunday nights. Maybe Boston Pops, too.
WFRO-FM 99.1 Fremont held onto the format for a long time (probably into the 1980s?), while they still had a good AM signal on 900 to do pop music and local stuff. They also added the Cleveland Indians games to FM, I think.
WQTE-AM 560 from Monroe was probably the first example of the format most people knew in the Detroit area. My parents listened to it on Sunday mornings back in the early 1960s. And WEOL-AM 930 from Elyria also had a soft "BM format, and had a decent signal along the lakeshore to Detroit, and used a harp glissando signature with their ID. Like in the Rolling Rock beer ads.
WDBN-FM (94.9?) from Medina was something like a 300,000 signal with the BM format, but you still couldn't usually hear it in Toledo unless the Lake Erie skip factor was at work (in the summer, signals from Cleveland, Erie and Buffalo often strengthened for days at a time and came in in Toledo, which was a problem for the TV and FM stations sharing the same frequency 200 miles apart, like TV channel 24.
Who else? WBNS-FM 97.1 in Columbus was a big BM signal They used to pipe it into the University Inn at Ohio U in Athens 80 miles away. That, while students were treated to "death rock" on the cafeteria loudspeakers from the closed-circuit campus station called ACRN. Neither option, in my opinion, were very appetizing.
Detroit's WKNR-FM 100.3 was, I think, the big FM version of the BM format in Motown, but went to soft rock as WNIC-FM earlier than many others made the switch. WOMC 104.3 FM also did it. And 95.5 FM was "cosy" for awhile.
There were probably also several other small town FMs that did this format until they found something better to do, or let the boss' son experiment with something different.
Funny, but while beautiful music was a filler format for many fledgling FMs, once the FM band started to catch on, not many held onto the format for long.
-- Goldilocks