Filling a Region
 

Created a free form polygon using the line function. Now I would like to fill it with a pattern, but since it's not an object, I can't do it. Can I convert to a "region" or object? Or is there a way to use one of the preformatted object styles and them adjust the midpoints to make a polygon?

I'm afraid that this isn't possible -- The line tool is for connecting shapes to each other to establish hierarchical relationships. However, you can use the Pen Tool to do pretty much the same, and apply fill colors or gradients to the shape you create with it.