I got what I wanted, or at least good enough for what we needed at this point. I had never worked with rendering before, and as usual PTC's help center was esentially useless on the subject. The solution was to set the output size to an (in my mind) outrageously large number, so that when the image is sized to fit on the 36x24 paper it's actually being shrunk instead of stretched. This greatly enhanced the output resolution. Add to that some wall and floor textures I found on the web and the image is quite nice if I do say so myself. Thanks to all who gave me ideas.
Chris Benner
Autodesk ® Expert Elite