Compare PDF to Word - Large Document / Book

A friend of ours has written a book. He typed it on a typewriter, wrote notes in the margins, etc. The next step is to have it made into an electronic version... so we scanned it to PDF (300 pages) and ran OCR on it (convert to text). What we need is someone to go through the PDF and update the word document where the text or handwriting was unclear. No editorial experience necessary, simply reading and typing what's wrong and/or missing. Any section that's not clear, simply mark and we'll handle it. We just want someone to give it the first pass. Doesn't need to happen quickly... so, fit it into your schedule where possible. Perhaps we could create milestones for blocks of pages (e.g. 50 at a time). Check our employment history, we have a good reputation with reliable payment. Milestones have worked well for us in the past, but we could do a flat price too.