If i recall correctly the perfoma didn't have ethernet as standard so file sharing would be diffcult without an ehternet to localtalk bridges, I'd say your best bet is to buy the cheapest USB hard disc caddy from ebay, wip the ide disk out the performa put it into the enclousue, plug it into your new mac, mount the drive, copy you stuff off it then bung it back into the performa. If they had the same case design as the 6200 (i think they did) then the hard disc is only few screws away once you get the front facia off. As for reinstalling the perfoma without a monitor, well I'm afraid that ones a bit more difficult!
I break stuff.