Near to the Marinemuseum is the ferry to the island of Texel, tickets to Texel costs 2.50 Euros for a return ticket and takes around 15mins to travel there. The island itself is very beautiful and flat so perfect for riding bikes and is a very nice day out:
In the centre of DH you will find all the usual shops and restaurants (including fast food like McDonalds) also bars and (of course) coffeeshops. You will find some very nice secondhand shops which change stock everyday because they are very popular. If you have a bike and are in the centre of DH then a nice bike ride (or walk if you don't) to have is to ride from the dike near the Marinemuseum down to the lighthouse and then from there go to the Fort Kijkduin which takes you straight down the the sand dunes. Usually when I do this bike ride myself I see one or two seals in the sea which are a common sight here.