Removing Brick Mortar Lines from Building Mural

If I wanted to remove all of the brick /mortar lines from this image to create what looked like one continuous painting (minus the holes where the window is), what would be the best way to go about it? I'm currently trying a combination of eye dropping/painting/blurring and occasionally spot healing individual pieces (see image below - note the rays and crop rows in the upper right hand corner and the roof of the turret on the house just below the center of the image).