The posted coordinates will bring you to a trailhead sign with distances for various points shown, and the park rules displayed. To find your next waypoint, add up the distances displayed to the various rest benches. Ignore any decimal places in the final. Add to that the number of letters in the last word in the brown sign. Take your total and add it to the posted north coordinates. Call your new number ABC. ABC check sum is 13. Now you need to determine DEF, which will be the new west coordinates. D is the number of months the park closes at 7:00 pm. E is the time the park closes in August. F is the Chapter number of the Somersworth Ordinance governing the park divided by 10 (ignoring all decimals). DEF check sum is 18.
After a pleasant walk, you should be standing near a red pole. To find your next waypoint, rearrange the north coordinates to AB (F-C). Thanks to NHAnimator to point out that F-C = J. Look at the red pole and find (or guess,.....okay, it's 5) the fourth number from the top. Subtract that from D and call it M. Your new west coordinates are MEF.
At the next waypoint, count the horizontal sections of the black bars that you can see. Multiply that number by 4. Subtract it from ABJ. West will be M (E-B) J.
You can grab the final on your way out.