The toolkit has always been publicly available for download, so feel free to use it however you like. If you can finish what's there, I'm all for it. I had hoped to find the time to add the finishing touches, but just haven't had the time or motivation for a while. If I remember right, the main things left are implementing festivals, marriage/children, and more depth to the communication system with villagers. Everything else at least partially works I believe (except probably a day/night system, but a simple one should fix that up pretty easily). Maybe one of these days I'll pop back in and have things fixed up.
If you make changes and improve it a bit, feel free to re-post it in another thread (or even other forums, for that matter). Just make sure that everyone in the credits list gets credit for it for the things they did. I may revive the original thread if I do come back at some point and finish it.