The cache is only accessible by walk or bicycle, if you want to go by car you can park your car at the Zandvoortselaan near the Ecoduct, From there it will be a 25 min walk to the cache. Dogs are allowed in this area. The terrain is part of Natonal parc Zuid-Kennemerland and accessible between sunrise and sunset, it is not necessary to climb over the fence.
The Atlantic Wall ran from Norway, through Denmark, Germany, Netherlands and Belgium to France to the border with Spain. The defense, which incidentally was never fully completed, consisted of bunkers, cannons and minefields. In some places, the bunkers have been preserved, including in Zandvoort, Katwijk, Noordwijk, Scheveningen, Hook of Holland, various places in Zeeland, Ostend, and in Normandy.
the part of the wall you will find near the cache is located on the East side of the stützpunkt gruppe Zandvoort."
http://www.atlantikwallplatform.eu/en/home/country/places/region/poi?poi_id=267