Clueless where to start

I hate it when I have to pick up a project right from the middle.... and worse if it entails something that is already in use and requires massive re-write.

Supposed to revamp the website but there's so much to do!! Every part of the website and its component is in use and being constantly updated at the moment, but the revamp entails a whole re-structure of the site as well as adding in new applications, systems and when "lived", training of people to handle the content updating and management too.

Grr.... this is one colossus of a project and I just dread lengthy projects....