Thanks for the good comments, gentlemen. I agree that the small cracks shouldn't pose a problem. We certainly encounter worse on many courses.
My plan is to compare rides on this new course with a previously established one within the same hour or so to see what differences there may be. I don't expect any significant difference.
Though your technique is to be commended, Guidos, I have had some success driving nails into concrete. I will look up the specs on what kind of nails I have used and report on how it goes when I certify the sidewalk course. I remember that the process requires slow, careful hammering. When done properly, the nail goes in without bending or shattering the concrete.