Okay, I guess I should post more details.

I was hoping to notch the studs roughly 3/4"X3/4". Just big enough for
a a a 14/3 romax cable. The wall in question is 20' wide and 16" high
at the highest point, If I notch the studs, I would have to notch 5 of
them. I have no access from below. I have very limited to no access
from above. I have not been yet figured out how the wall is built. The
wall is insulated. Opening up the walls and center drilling will be a
major job. Wider casing is an idea. Thew current molding is 4". The
doors open to an covered porch (this is on the 2nd floor).

I am also concerned about how practical this is. Our bed does sit
high. The center of the TV woud be about 4 feet above eye level. The
mount I was planning on using can tilt 10 degrees down. My other
option would be to mount it in the corner but then you are twisting
the head to watch TV. However that be a better answer.