[Mark Nord]

Sorry I can't follow, what you are trying to do, and maybe I sound blunt, but..

With PRS+ and card-scan fully disabled you can always browse the content of the card via BrowseFolder, and carry your whole library with you that way.

It is true that to read a book in this mode, it is copied into IM and opend from there.

But how, by all means, can you read 2 Gig books at once?

Read the book, finish it, delete it (from IM, it is still on the card) and copy over the next one.

Or am I missing some thing, and reading isn't your primary goal with all that books?

Edit/Add: after reading your post twice (some line breakes may help) it is very likely that one of the books on the card (as stated by luvduchovny) is causing the problems/restarts of the reader. (I assume they are all from trusted, high quallity sources, but who knows...)
If you want to spent the time, erease the card, copy some 100 titles to the card, let the reader scan, and add the next bunch. This way you may be able to narrow it down to the problematic file(s)