Konrad is right: use Word or OpenOffice, with Word being rather nicer to work with. LyX is not too bad, but it is not nice to ask family and friends to install it. I recommend Word where you can.
Work with the source if you can, don't detex, and don't work with the PDF, since the back and forth generally causes problems, needlessly missing corrections or introducing errors that you are likely to miss.
You can put the source text directly in Word, and highlight regions that don't contain text to be reviewed (say, middle grey on pale grey), and it is possible to tell Word to make these regions uneditable.
Switch the document to Track Changes, and send both this document and the PDF to your reviewers. If you send the text to several people, it is likely that one does a far better job than the others and if you are lucky returns them as tracked changes: work with this text and add additional changes from other comments from your friends and family.
A nice bonus: Word's spelling checker is good, and you can set the language of the highlighted regions to non-spellcheckable, but please switch off the deeply problematic grammar checker.
Then at the end, with all changes accepted and rejected, and all issues handled, turn your Word document back into plain text, run it through Latex, and give the output a last, careful read through.
I made some notes on working through changes on my weblog: Reviewing Edits.