Handouts Q...

Is there a shortcut players can use to call up a handout in their journals from the chat window?

There are keyboard shortcuts and advanced shortcuts available. I don't see one specifically for handouts, though if you have advanced shortcuts active, hitting 'j' will take you to the journal tab. If you check handouts in the Roll20 Wiki there's a bit more information in there. The GM can drag the handout from the journal tab onto the player and it will open immediately as well as give them permissions to view the handout.