I glued the front door in place, making sure it was level and centered in relation to the portico.  I then added the supplied interior trim, painted Vintage White by Folk Art.  I used spackling to fill in any gaps and touched up the paint.  To finish the threshold, I used a small piece of quarter round trim stained Minwax English Chestnut to match the floor.

The trim had broken at some point, but I left it as is for installation.  Just a hint of the break is still visible in the photo above, so I might go back and work on that some more.

To hold the acrylic insert in the upper arch, I glued in a small strip of bass wood painted to match (shown here unpainted).  This should offer enough stability to keep it from falling backwards as it is apt to do.  :\

It does show a little from the outside looking in, but it's not glaringly obvious.  It just looks like a structural part of the door.