Trying blurring the source image a little to help blend it with the background Best of Luck

Still too sharp edged in the front, making it look cut and paste with a bad distortion. The dark edge is part of the problem. Very creative idea, though!

You could have kept the nails, burn those letters into the wood, choose a rough font, and place it like a sign post. on a field or even in the original BG. It would have been easier to recognize the source this way.

I agree, this is totally not noticable that it was the source image. Sorry :/

cutting the board from the middle and using clone stamp tool ...make result look like as in step 1 of subs