I saw the regular book is 731 MB and the print friendly book is 135 MB. Each is only 145 pages. Are there any settings you could tweak to reduce file size? Running it through my usual compression program for PDFs was able to cut the big file in half, but that's still 350 MB.
I also realized every page is an image. None of the text is selectable. I'm not a PDF creation expert but when I create PDFs for other projects the text can be selected by default.