Sorry to be late to this party; just joined the forum.
I'd like to point out a book that specifically addresses digital legacy--
Take Control Books publishes
"Take Control of Your Digital Legacy."(My connection is only that of a purchaser of quite a few books from Take Control.)
Take Control of Your Digital Legacy is almost 200 pages (in any e-format) specifically addressing the question of how your loved ones/heirs will deal with your electronic ephemera.
The link above will give you a table of contents and generous preview of the book.
I've bought several copies for my less tech-savvy family members; they've found it useful. I've found it useful to not have to repeat myself and do all the training that's in the book!
And yes, even though I think of myself as very capable tech-wise, I picked up some good tips also.
Hope this is helpful!