I do it every week. First, I don't use Ghost. That doesn't play as nicely as Acronis TrueImage 9.
Here's the easy way. Get an external 2.5" Firewire drive case, and put the taregt drive in it. Since most laptop Firewire ports are 4 wire, you need a 5 vdc power source - good cases come with them
Then just CLONE the laptop main drive to the Firewire external.
What I do after that is swap the drives. That way I know the cloned drive is good, and the formewr main drive can get a rest. But you know it is a 100% good drive in reserve. That's what I call it - a reserve drive.
You can also do it with USB 2, but it is a bit slower.