Is there a set of standard best practices for compressing and adding text recognition to a scan of a book chapter? I'd prefer open source tools, but I'm hoping there is an existing script that reasonably does these two functions to bring PDFs to reasonable size and usefulness (hopefully in batch)
The answer really depends on your needs, time you might be willing to invest, money you might be willing to spend (for commercial software), and what you are going to do with the result (is it just for your own reading, or do you plan to distribute it).
A couple of open source tools that might help you are k2pdfopt and ScanTailor. They can both clean up scanned images, de-skew them, and crop them. k2pdfopt can perform OCR (using the Tesseract OCR engine). I believe they both do batch processing. If you have MS Office, MS Word also will automatically OCR a scanned PDF and convert it to .docx format if that is helpful to you.