Hi Matt, thx! You're not looking at a causeway but to the bifurcation dam inbetween Europoort and New Waterway. This dam is not public accessible. The dam is separated by Breeddiep from de 'Landtong van Rozenburg' (spit of land of Rozenburg), which is about 5.2nM long. This 'landtong' is public accessible (road and bicycle tracks). There's a ferry from Maasluis to Rozenburg and a small bicycle ferry from Hoek van Holland to Scheurhaven (tugboats) (opposite Stena Line) and Maasvlakte. Very nice area indeed with beautyfull views! Hoek van Holland and Maassluis have a good light rail connection with Rotterdam. There's a bicycle track following the north bank of the river from Hoek van Holland to Vlaardingen.