Quote from: _jacQues_ on April 25, 2016, 07:23:40 PM

1) What is a safe way to split a key or wallet file? (or maybe on paper?)

What about a 2-of-2 multisig address? Multisig is already fairly common and in the future, it will probably be more common so they can look up guides for how to use multisig.

Quote from: _jacQues_ on April 25, 2016, 07:23:40 PM

2) How to provide simple but adequate instructions on how they can combine those keys or wallet files?

You could tell them and show them how to use a multisig wallet or point them to a guide on how to use one.

Quote from: _jacQues_ on April 25, 2016, 07:23:40 PM

3) How to explain in lamers terms where and how to spend BTCs?

Just show them a wallet that you think they should use that has the multisig functionality (like Electrum) and demonstrate how to send Bitcoin to other addresses. Make sure you remember to include something about change addresses and fees.

As for where, you can point them to various sites such as coinmap.org which show where Bitcoin is accepted in physical stores and show them sites like newegg where Bitcoin is accepted online.