I've seen business offsite backup that used sneakernet, in one form or another, so it's certainly reasonable. In those cases, the backup (tapes) were simply removed from the premises after a backup, and taken to a different secure area.
If you have two transportable backup media, T, and T2, simply backup to one and take it to work, and bring back the other. So one is at work, safely offsite, and the other is at home, ready for the next backup.
Think about the process for restoring in the case of a house fire or some other disaster. That should help drive how you do the offsite backup.