Hello, Hassodog64;
Sorry if I'm a bit late responding (fourteen months ain't a 'bit', it's a BYTE), but did you get your P-brake cable taken care of? I replaced the rear cable on my '66 GS a few years ago, but don't remember which internet vendor I bought it from and can't find an invoice or shipping order. However, I do have Buick and '67 Chevy shop manuals from which I could grab some pics if it'll help.
GSGregg