KNUA would eventually become the predecessor to KWJZ, airing smooth jazz circa 1990.
Like a couple other people here, I had no idea Enumclaw had a Three Sisters Mtn. Apparently it's closer to Wilkeson. At 4000+ feet, it's about 500 or 600 ft higher than KXXO's old Rooster Rock site. I wonder how far KBRD's old signal got out. Wikipedia says it had some signal issues near Lynnwood on 63KW. But at 4000 feet? Multipath from nearby hills I assume.
When 96.1 was on Rooster, they were SOLID with a few fuzzy spots all around Snohomish and north King County. At least until Vancouver took over by north Everett or Marysville. Loud and clear at Ocean Shores, also variably heard in Portland suburbs too. I could see why they did move to Capitol Peak - not only because of the 96.3 move by KWLZ, but also less need to travel a steep and icy/snowy road to get to the xmitter in winter. The one thing I've noticed is that they do great as long as you are south of Seattle, or right at the waterfront up to Mukilteo/Edmonds. Eastside areas are fuzzy and multipathed. Noticed that with 102.9 and even worse on 96.9, before I moved over to the dry side of WA.
Also, re: KONG TV, I wonder, had they gone on in 1984 with the CP, would they have gone the low-budget indie route or more religious? I wonder if that big library of classic TV shows they had in the late '90s (Hawaii Five-0, All in the Family, even old movie serials!) was designed to be their format in 1984. Remember, the original KONG CP was not KING Broadcasting's. Also seemed interesting that they wanted to use Cougar Mtn even though their license and (not-to-be) studios were in Everett. Could have been a Snohomish County-localized indie.
Finally on cable, yes, Seattle had cable early on. Of course, it was Astoria OR that got the first cable system in 1948 or 1949, whenever KRSC-5 was piped in. Ellensburg got their cable rather early too, early '60s. In those days, KIMA Yakima, KOMO/KING Seattle, KXLY Spokane and a clock channel were carried. Sample ad for Jerrold Cable on page 5:
https://news.google.com/newspapers?nid=4oJvMfeQlr8C&dat=19620316&printsec=frontpage&hl=en