You should take your ZIP disk for each computer and the printouts you made, and place them in a secure location in your shop. You should store copies of these in your off-site backup storage location. The major purpose of off-site backup storage is to enable disaster recovery, and restoring each host onto replacement hardware is a part of disaster recovery.
You should also have several restoration Linux floppies or CD-ROMS, and possibly some ZIP drives in your off-site storage as well. Also, have copies of the rescue linux distribution on several of your computers so that they back each other up.
You should probably have copies of this HOWTO, with your site-specific annotations on it, with your backups and in your off-site backup storage.