Syncing without iCloud
iCloud itself doesn't sync music; iTunes Match does that.

A good solution might be to use iTunes Match to sync all the music between computers. In my experience with iTunes Match, all the complexity is up-front; after the initial upload, getting new devices on it and using them is super easy.

With Match enabled, just sync the iPhone to the iMac like you would have in pre-iOS 5 days and the notes won't leave the two of them if you don't use iCloud.