.. How do I find the password for the green cards?

You'll find the password for these cards after you get into the safe within the safe in the fireplace at the cabin in Loch Lomond.

How do I open the safe inside the fireplace?

Inside was Mom's MP3 player. If you can get it recharged, it'll give you the green password.

How do I play Mom's MP3 player?

When you get the password, enter it into each green card to learn more. The important thing you'll learn is in the handwritten note that tells you how to reach the Scientist -- listen to the record, which will tell you which letters from "Jabberwocky" to decode.

Confusing? Yes, certainly, but don't worry; Nancy knows what it means. When you get hold of the right record, she'll set the rest of it up for you. All you really need to know at this point is that the reason "Jabberwocky" is important is that it will tell you how to reach the Scientist.