I don't have pictures but what you can do is go to Hobby Lobby or Michaels or a craft store, get some 12 x 12 scrapbook paper (they might even have Disney themed paper) and draw a calendar on it. You can then add stickers counting down the weeks.
We did this the last 2 years and started out about 15 weeks so we had 4 months full of calendars. The kids loved it.
We also logged on each Saturday and looked at the webcam and said "In X more weeks, it'll be OUR turn to get on the Mickey Boat!!!"
This year is KILLING me because they don't know! But the fun I'm having in preparing their Christmas surprise is making it all worthwhile!