you need to understand something first, your model is completely made up of triangles. there is nothing wrong or unclean about those edge lines showing on your model. if your model is an editable poly go into polygon su-object mode > edit polygons rollout and activate edit triangulation (with edges faces display for full effect (F4)). you will see that your model is made up of triangles.

if you do want to make those edge lines invisible then convert the model to a editable mesh, then in Edge subobject mode select the desired edges and open the Surface properties rollout and press Invisible

Thanks I will try that.  I did not realize that the geometry was made up of triangles and was concerned that these edges would appear somehow later on when I added materials? 

I was experimenting with (2) methods to do cutouts on my walls without usining the boolean command.  I made this box using a simple spline then drawing on the front view my windows then I applied simple extrusion modifiers for windows and doors as oposed to using the slice tool that appears to be more work?  I am not sure if one way over the other yields better end results?  For me this was a simpler approach coming from the architectural world.

Thanks for the thread link!  Very helpful.  I will check out extending the sides of the openings and apply a material to see how it all renders out.  In one of the threads it seems that box modeling method is good if you want to manipulate the project later on, and if you don’t mind more polys?
So many ways to do stough in this program - truly a double edged sword!