OOOHHHHH! That is Awesome!!!!I'm lost on this one too.
I hosted a Disney Cruise Party last fall and I still have the sign. It's the Fabulous Five in their cruise wear with the ship behind them and it says "Welcome Aboard". I can have it stuck in the ground outside the front door as their final clue.
I'm still debating revealing here on that Sunday morning or just tell them we are driving Nana to Aunty Linda's and that we'll tour DC while there. Then have a scavenger hunt of clues in DC, that will lead to your place. If I do the later, would you be able to attach to the back of your sign an envelope that will contain the Mickey letter about the cruise? Oh, and if we wait till then, that means my youngest is likely to be bouncing of the walls all evening. Are you prepared for that? Really I have no idea how they will react, but I know when Tim gets excited, he can get Crazy Hyper!
Oh, you make waiting till DC to plant clues much more thrilling!!! I'll let you know. That is a most awesome sign you have!