i don't think that paper note as of securing their investement for 20 years or >?, would be good introduction to the whole project of Bitcoin network.
My 64 years old friend is writing notes but forgets where he put them next day...
i was thinking about exactly oposite such as encrypting private key in text file on the same media and giving password to the parents so they can be sure that grandchildren don't have an access for this certain period of time.
The solution i guess is in the software, so any of these people (with minimum computer skills) were able to transfer a wallet loaded BTC with a few clicks to selected media without seeing scripts, codes and the rest more confusing sea of symbols.
Don't know how many of you are familiar with Sugar on the Stick linux distribution but it's learning platform for kids or other groups of ages with no computer experience at all. This what i imagine woud work if there is simple graphical user interface with a few clicks making a transaction for a permanent storage.