Okay, I just sent out some postcards to the four Disney addresses by going to AmazingMail.com. I took this image of a screenshot that I grabbed on the last day:

...and sent it with the message
"Save Our City
Buy our Game
Help Us Build A Whole New World With You
#SaveCoH"
along with a lengthier message on the back. I received a warning that I hadn't made the screenshot at the optimal dpi and that it might appear fuzzy or pixelated, but it seemed okay when I viewed the preview.
I also sent another such bit of mail with the same image to our friend Mr. Kim in Korea, thanking him for all he's done for us (words that felt wrong to type) and asking him to sell the game. I sent a copy of that one to myself, so ideally I'll see how the image will look to the recipients.