What should I do...? (guy trouble)?

This guy that I slightly liked/maybe like just confessed to me over Facebook that he thought of asking me out. Trouble is, he's moving to another state and going to college. I'm just an incoming sophomore. He's really nice and definitely not someone disgusting so I don't want to hurt his feelings or anything. How do I say that it's just not going to work out? Or at least what can I answer to "soften the blow"?