The best solution I found as an alternative to an off-site copy is to set up a USB drive and something like a Raspberry Pi in my car. When I pull into the garage, the house server senses it and syncs new data to it.
This can be supplemented further by having it auto sync to a computer in your office whenever you pull into work. Add in some monitoring so you can get a phone alert if any of the synced copies are more than a few days out of date, and you are almost golden.
This can be supplemented further by having it auto sync to a computer in your office whenever you pull into work. Add in some monitoring so you can get a phone alert if any of the synced copies are more than a few days out of date, and you are almost golden.