In 5,000 year, I expect gold will be a by-product of our cold-fusion reactors. There'll be more of it than we know what to do with. There will be landfills full of the stuff.
Gold is
currently being produced as a by-product of nuclear fission, albeit in a tiny ratio, along with more expensive elements. However I don't know if it's profitable for reprocessing facilities to extract it from used fuel or whether they're actually extracting the expensive elements other than
137Cs. You might want to research further, it's interesting.
P.S: Simplicity and/or standardization and the key for information preservation along lifetimes. It's clear to see paper backup archives both. If I were to use paper backup I would store it together with a written english and spanish (My native languaje) description of it's format and the decodification process.