I think a half-pillar frame around the opening of the entrance could work. Nothing baronial or Roman or Gothic, you understand. Very simple.

If I were to do that I would also use big splashes of white in the garden -- white petunias, whatever.

I would widen the walk to the edge of where those white rocks are...this makes the walkway more inviting and easier to walk on. This would give you room to put two tall glazed pots in some snazzy color and with greenery to dress up that front door area. Put lights on the front of the house, on either side of the door alcove, as well as some stylish house numbers to make the entrance more obvious and inviting. It looks like the front needs gutters...I would add those for a more finished look and water control. Also, make sure you have good overhead lighting in the door alcove, it looks dark from the photos.