Suggestions on a Freehand conversion
 

I created a campus map in Freehand (long before Adobe bought and killed the app), and I'm planning to convert the map to OmniGraffle.

I'm not certain of a good way to convert this type of document, since all of my rooms are incomplete rectangles (with an indicated door) ... I've included a portion of the map as a sample in the attachment.

I'm looking for suggestions. How would you create this?
Chuck