Clearly you've put a lot of thought into this. My preference is to use an on-line backup service. Mine makes two mirrored backups at two widely distant remote locations. My software can Image, or Zip/compress a file small enough to upload daily. This is automatic, and unattended. It accounts for any changes I've made that day. It can be encrypted.
Retrieval can be from anywhere, or anyone to whom I've given access passwords. I have on my HD one folder into which I scan and keep updated critical personal documents.

YMMV, but for me this works well and costs ~$5.00 per month for a 140Meg compressed file. Costs may vary: mine is a part of my telephone DSL plan.