Find a common wall from the first level to the second level. Easy way to do it is if you have a closet above another closet. Cut two cheater holes the size of single gang boxes in the back corners of the closet. This will allow you to easily drill holes in each top plate. Now you have an easy way to fish the wire from lower level to the upper level and then to get you into the attic above the 2nd floor. Simply put in retro (afterthought) boxes into your cheater cutouts and put the appropriate blank plates on them. Its only a closet right? You will never even see these plates after you cram your closet full again.
My Theater http://www.aquacatt.net/theatre
My Theater http://www.aquacatt.net/theatre