unfortunately, by the time any sort of home-processing becomes viable, all the existing film will be hopelessly out of date and magenta-shifted. >:-/
I have used some K64 which was twenty five years out of date and always kept at room temperature and all it had was a slightly cooler look than normal so I don't think we need to worry too much about it.
"People who say things won't work are a dime a dozen. People who figure out how to make things work are worth a fortune" - Dave Rat.