Welcome to the forum. As you have seen there is a great deal of help here.

Now to your question.
I can't give an exact answer at the moment. This is what I would do:
I would copy all the files that have been changed in the Drive:\BB folder.

What I cannot answer is the resultig question:
Can I access these files directly on the cloud? My wild guess is "No."

Again, what would I do?
I'd write a small DOS batch program that I'd run to open BIAB.
This would copy all the files from a certain cloud folder into my BB folder, start BB and after closing BIAB copy all current date files from the BB folder to the cloud.

I have not done this yet with BIAB and my experience writing DOS batch programs has been maintained like some of the seldomly used rural roads in a desert. There are weeds, sand, stones and pot holes galore prohibiting smooth driving.


Desktop; i7-2600k, 8 GB mem., Win 10 Pro, BIAB 2017; RB 2017 - latest build
Laptop: i5-2410M, 4 GB mem, Win 10 Pro, BIAB 2017; RB 2017 - latest build