Thanks, guys! There is no good place to drill a hole in the piece or toenail it as that section sees a lot of sun and rain/snow (front edge of porch, faces east). Plus, it's already painted. Fortunately it does not see any foot traffic as it's in front of a post. I am going to go with construction adhesive, as the back end will be held in place by a repair piece I'm making for the post.