1. In a perfect world (sigh) a back up would occur of the NEW books I added that day (with covers) along with a daily metadata.
Microsoft's ROBOCOPY is a free command line replacement for XCOPY that is designed for reliable mirroring of directories or directory trees. It's a great tool when you're trying to backup a folder to another location. The switches can be set to remove files in the destination when they are removed from the source. Probably the most useful feature is to ignore files that haven't changed; the initial copy may take a while, but subsequent copies will finish much quicker.
Here's a sample command line I'd use to backup the Calibre library:
robocopy "c:\path\to\Calibre\Library" "e:\Backup\Location" /s /purge /xo /r:1 /w:1
This will simply copy all files from the Library to the Backup location, including all subdirectories (/s). It will delete destination files and directories that no longer exist in the source (/purge). If destination file exists and is the same date or newer than the source, don't bother to overwrite it (/xo). If a file can't be read for some reason, it will retry 1 time (/r:1), at a 1 second interval (/w:1)