Your E-model system is gorgeous. I've got an S-model (with a subframe of course) myself but if I had an E, I don't think I've ever seen anything else that could compare. At any price.
To take such a capable bike and make it travel-ready in this manner essentially makes it a whole 'nother bike (for the better!) And without having to BUY another bike.
Good luck with this project!
Streets still unseen, we'll find somehow. No time is better than now.
-Steely Dan 1972