ok, I tried the box in the upper left side of the drawing, started the polylinejoin command and set my fuzz factor to 6, it went through and joined all the segments to 1 closed polyline. I then ran overkill, just for the fun of it, and it erased 108 overlapping/duplicate objects, leaving me with a 4 sided polyline. There is currently a linetype established, but due to the drawing scale it is difficult to see, so I change the linetype scale of the object to 24 and the dashes looked fine.
See here:
http://screencast.com/t/Z7zYmeLa
sorry my command line isnt visible, it is difficult to capture videos with such large resolutions, so I generally try to capture just the pertinent area.