If you keep the exposed or unexposed material dry, in the dark and reasonably cool then you should have no problems.
Just don't mix it up! (Not that I'm talking from experience or anything
)
Don't forget that cyanotype paper was commercially available, which means it must be relatively bulletproof.
Longevity is often a function of the paper base and it's ph.
For example, I had lots of problems with Fabriano Artistico. Nice paper but I had to treat it with oxalic acid.
I use the Mike Ware formula coating (quite easy to make at home) coated onto Bergger COT-320 paper.
This combination has been trouble free.
Good luck
Simon