Camping in Netherlands

Hi, I live in The Netherlands but never have been camping - and soon will have friends visit abroad.

A friend is getting married and wants a very calm bachelor party weekend with 4-5 friends. Simply some walk/hiking, potentially fishing, beers, smoking too hence why the stag wants to come to The Netherlands for this.

It would be camping with tents. We will have a van/car.

We’re an older crew so this is not a get drunk/messed up kind of bachelor party.

I know there are many camp sites you can rent space at for families and such, but we’re looking for something a little more secluded, without children, or people really, and I’m aware wild camping to not legal.

So any ideas or places you would recommend would be greatly appreciated!