Hi Andrew,
Most of the year I work in Holland, between Delft and the north of Rotterdam - so you may find the following useful:
Koningshof (Rijnsburg is near Amsterdam) is a part of the group that also owns the popular Delftse Hout camp-site (a city centre site just outside Delft) and these two sites I think of as "city centre" sites - so are like the Caravan Club York Rowntree site - relatively small pitches but with good quality toilet blocks, clean, etc.
High season for Koningshof includes the busy weeks at the Kitchen gardens (Keukenhof) - so you won't get a discount (or much of one) when the gardens are open
Something like 25% of Dutch families own a caravan - Dutch drivers know about caravans so don't expect any troubles towing - except for three items:
1. The Dutch speed limit on motorways (when towing) is 80 kph
2. In Holland, the only legal way to attach the caravan breakaway cable is to a fixed point on the tow-bar - looping over the tow-ball is illegal - and will attract a 30 Euro fine - and this is regularly checked at the Dutch ferry ports (and no where else).
3. Road junctions and roundabouts - take care - there are always two stop points - one where the roads meet and one just before where the cycle path crosses your road - and cycles have priority
Most Dutch people speak English, but it's nice if you learn a few Dutch words - like "Dank U" (Thank you) - "Alstublieft" (Please - pronounced AL SHOE BLIEFT - and is used everywhere) - "Nee" (No - pronounced "NAY") and "Ya" (Yes)
It's always windy in Holland, particularly the west - and temperatures are very similar to the southern Midlands - Oxford / Birmingham - and can be rainy and wet (so called English weather)
Other nice day trips - Delft, Leiden, Amsterdam - don't take your car - use the excellent and fairly priced train / tram system or Park and Ride (P+R signs)
Anything else, like how the Dutch drink beer or where to eat, just ask
Robert