|I think I'd do it a different way. Your company may well be doing what it wants though.|
One problem is with the carts. They do go bad if you use them everyday.
Second is the people having access at their home. I would not let my companies data off site in personal vehicles.
I'd consider a two stage backup. One is to secure the data center. Second is to create some form of backup daily or by the hour or as your data demands. Could be tape or another server. Tapes should be tested too if used. Making tapes and never testing is silly. They should be secured in fireproof safe.
Last would be to pay for secure off site backups.
It all depends on how much you want to secure your data.
You would be surprised to know how far banks and other financial institutions go to protect data. We used to make systems and they started at 8 way redundancy.
Why did it take me over a year to phone in a problem to ATT?