Kids will love 'Basic' camping and make loads of friends on site, but do try and get to our Meets which are all very well priced and family friendly, if you need help with anything just ask someone.
Thought: well worth camping fairly close to home for the first couple of trips. Its still an adventure and you can pop home if you've forgotten anything, and give up if it pours.
Big benefit of sites you don't have to book is you can plan it, not tell the family, and not go if the weather is bad, but Hey Ho, nice surprise treat if the forecast is good. (I'm a natural tight wad.)