That would definitely be a lot of working, moving them. I'm curious, why would you delete them from ff.net? Lack of traffic? Trolling? I know for me, I tend to get far more hits etc on ff.net than Ao3, and I do like to support ff.net as it's still very much a 'gateway' into fandoms for new people. It has it's drawbacks but I've found some wonderful folks to follow and chat with over the years there.