I have PS+ to use with the Vita, cannot use it on the PS3 with CFW.

I have a 300GB HDD in my PS3, but there's only some games on it that didn't work at the time from external disk, and I don't have any DLC on it, so I think it's fine. Only stuff would be game installations, but the can be installed again, and also some of them are on the external HDD.

I got 75% of my savegames on a USB stick, some games don't let you copy them though, only in the cloud.