I found the best method was to first split into side-by-side pages and then to convert that result with autostraighten and OCR.
Code:
k2pdfopt book.pdf -mode crop -dpi 50 -fc- -cbox1 0.36in,0.75in,3.22in,4.32in -cbox1 5.35in,0.1in,5.07in,8.36in -cbox3 0.41in,3.79in,2.56in,3.08in -cbox4- 0.66in,0in,4.28in,8.73in -cbox4- 5.41in,0in,4.67in,8.73in -o booksplit.pdf
k2pdfopt booksplit.pdf -p 2-,1 -as -mode fw -ls- -n- -w 3.39in -h 4.55in -dpi 165 -de 1.5 -ocr t -ocrlang ell -o final.pdf
The various -cbox commands crop out certain parts of page 1 and 3 and then all the rest of the pages are split. The second command fits to the page width, straightens, and adds OCR. I've attached the result.