There are lots of good replies here, and I think Pooya87 makes a good point; you could just write down the corresponding number of the word from the word list to obfuscate the words themselves, and just have a strong passphrase to encrypt the wallet.  You could also convert those numbers to hexadecimal values to further obfuscate their meaning.  That should buy you plenty of time reach your destination and create a more secure storage method.

I doubt that most customs officials are looking for evidence of bitcoin these days.  That may change in the future, but for now I think Poker Player might be overthinking the issue.