That's an interesting challenge.
You can use vectrosity here. But the playmaker actions for it doesn't support dynamically adding nodes to a path. Not yet. So, I guess you will have to make a custom action to access the arrays of vectrosity. Now, to make the path, you can find mouse pick action handy. Lay down a series of nodes and feed the positions of these nodes into vectrosity for visualization.
This can be tricky for a noob though. May be Jean will be kind enough to make this action. I think vectrosity is already in his Huge Todo list.