I think you've got a good shot at picking up things like trading card/sticker boxes as people actually saved/collected those, and probably even a Bazooka box. Bazooka boxes show up somewhat regularly, though if you're specifically looking for a 1970's one, that might be tougher (60's boxes seem to surface more often).
The other material, the candy/bubblegum stuff is going to be exceedingly difficult to uncover. In my decade + of collecting candy/bubblegum material, I cannot recall more than a few Gold Rush display boxes (scored and folded/used) that have ever come up for sale... maybe three or four? I think I saw a 1980's one pop up early last year.
I have a good number of Gold Rush display box flats and proofs that I've purchased over the years, representing a few different eras (and box/packaging designs) of Gold Rush, and even a 1970's UK Topps/Trebor Gold Rush display box proof - which is amazing. In fact, I have more Gold Rush display box flats or proofs than I do actual scored-and-folded display boxes.
The most unusual piece I have for this brand might be a scored-and-folded display box for Gold Rush Raspberry, which was out in the late 1960's - a short-lived, oddball flavor extension for the brand.
The thing you might be able to find would be some of the slightly beat-up printers flats which was a big find from 20+ years ago. Those are unscored and sometimes roughly cut display box flats, which included things like Gold Rush, Munchy Mummy and Garbage Can-dy. Some don't contain all the printed colors, but the ones I have for those brands did - they're awesome. So those are out there in some number, though I haven't seen them show up for sale like they used to for some time. That's the most likely place you might find them, historically speaking.
Still, like this unusual find of full Gold Rush display boxes that started going onto ebay last month, a new find could surface. Which would be pretty fun!
Also interested in Bazooka Joe, Monster Initials, Creature Feature '73 and probably a few others, but Gold Rush definitely "topps" my list, haha.