There are two seperate issues, keeping your data secure from the government reading it, and making sure you have a copy of the data you want on both sides of the border in case they do take your laptop. Both require different solutions. The first takes heavy encryption, the latter a cloud service.

Mind you the government does not have a right to your password - since it is stored in your mind and you have to basically testify to the password it is a violation of the 5th amendment. However if you have a physical key, they can get a warrant for the key, so use a password and some solid encryption and take multiple copies of data.