Sadly, recently TV has changed the product so it basically no longer allows free usage. So, I am looking for a replacement method for remote control of the observatory.
Wow, really? I did look at the TeamViewer site and it still says free for personal use:

Well anyway Eric is right RAdmin is good. GoToMyPC is also a possibility. Both paid but not too expensive. We use TeamViewer, and the Remote Access tool that ships with our software is the "receiver" for our commercial TeamViewer service.

I haven't looked at VNC for a while but it appears to have become a professionally supported product. It appears that they have a free version.