https://play.google.com/store/apps/details?id=com.koushikdutta.backup&hl=en
You can use this application to back up and restore relatively easily. There are tools for stock Android, but they're a little less user-friendly.
As for the Cloud sync from a programmer perspective, it's all right here: http://developer.android.com/training/cloudsync/backupapi.html
You could also use the new Google Play Games for achievements, cross device sync, etc, but that's much newer.