My nearest cousins were minimum 6 years, maximum 18 years older than me. Three of them babysat me or my sister at one point or another. About 5th grade I got my cousin Larry's comic books, amassed during his adolescence from 1968 to 1973. That woulda been the absolute nadir of the comics market - pretty much right before Watchmen came out. There wasn't a single title you'd recognize - they were all horror comics, a bunch of non-superhero Charlton titles and the like. I don't remember a single storyline, although I immediately knew what The Black Freighter was about when I saw it. The ads were amazing. For one thing, it conclusively proved that the toys my cousins had to play with kicked the shit out of mine. My Great White Whale is a poster I saw in the back of one of those comics. They used to have these spreads of all these posters you could order (for a dollar). Head shop shit in an era before Dark Side of the Moon, when Woodstock was still a disruption rather than an iconic event. Each image was about half the size of a postage stamp, but there was one of a man sitting on top of a metropolis of prismatic glass. That was kind of a theme back then. I still look for that poster sometimes; that one and the Cabaret Voltaire poster in Ferris' room. I've never found either.
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Holy childhood flashbacks! That second pic - that was one of my favourite toys when I was a kid, it was EXACTLY that except mine was orange. Loved that thing.
In Rockford Illinois there is an awesome record shop called Toad Hall. They had tons of old records, books, and posters. They might actually be worth giving a call. At the very least, they might be able to point you in a good direction.