None of the browsers I have will save field info when I save the page. You might be better off writing the paragraphs in notepad or similar and then cutting and pasting them into the form - that way you will have a record of what you have written come interview time.
If you want to complete it off-line, wait until the page has finished loading, then disconnect from the internet. When you're ready to submit the form, either restart the net connection manually or just click on the submit button (if your pc is configured to automatically connect when required).
Cheers