Upgraded - Want to sync my media

I have some questions regarding syncing my photos / iphoto, music/itunes and iPhone after I changed computers.

I had an iMac with 10.7.5 and 1TB Hard drive which I used to sync my photos, music and iPhone to and a few days ago I bought a new MacBook Pro and got a quick sale for the iMac. Being a quick sale I just copied all my photos and music to an external hard drive but not the libraries as I was in a rush.

So, long story short, I have my Music and Photos on a USB disk but no libraries.

My iPhone syncs to the cloud so I should be somewhat safe.

I have access to my Photostream through iPhoto on ML.

Now, I do want to sync my phone and photos and music to my new MBP without earasing the phone AND since the MBP only has a 128GB drive i'd like to keep the files/libraries stored on an external source (USB drive).

Is it possible / easy ?