Thanks Excon! You're correct about not legally having to provide a forwarding address, it's only if you want the security deposit returned.
I started doubting how I understood "within 4 days of moving out". I have always understood that as, you have 4 days after you move out to provide your landlord with your forwarding address. Then I started questioning "within" - 4 days before you move or 4 days after you move? I hate moments like this when I get myself all confused over simple english.
I'll be sending that bad boy out in the mail today - certified & return receipt, of course.
