Duinrell is more than a campsite. Firstly, it's enormous and boasts a theme park, plus an indoor and outdoor waterpark. The site is much bigger than we would normally go for but it is split up into smaller sections, so it doesn't feel as big as it is. Not all areas were open in April and our section was not full but you feel that you would still have enough space to relax, even in high season. We were in the Romantisch Kamp section, which we would ask for again if we revisit. It was nicely laid out in little cul-de-sacs with plenty of grass for the children to run about on. It's also well located as in it's near enough to the Plaza and the park, yet you still feel away from it all. The theme park is excellent and free (albeit included in the site fees). It has plenty for all ages. The indoor waterpark (Tiki Pool) has 16 waterslides and again, has something for all ages. The new outdoor complex is due to open in July 19 and the pictures look good. I'd just be a little worried of visiting in July or August because 970 pitches means almost 1,000 cars driving around and 4,000 people, and that's not including the day visitors to the park. I feel the roads would be very busy with cars, bikes and pedestrians, and the queuing times for the rides could be significant. That said, the site seemed very well managed and if we return to the area, we will go back to Duinrell.
In my opinion, Easter is a great time to visit. Keukenhof Gardens is open from March until May and it is a 'must see'. The colour is quite breathtaking. Apart from Keukenhof, all the flowers were in full bloom so the whole experience was enhanced. Wassenaar is the local village and well worth a wonder round. The beach is a 45 minute walk / 20 minute cycle and can be reached via off-road paths. We enjoyed visiting nearby Leiden and Delft. Amsterdam was an easy day trip (approx. 45 minutes drive) and Kinderdijk is well worth the 45 minute drive to see the windmills.
In summary, Duinrell offers so much for families of all ages. To justify the extra expense (compared with other sites in the area), it's advised to use the facilities as much as possible so please bear that in mind when booking. It's well located, well run and we can thoroughly reccommend it.