Spent a weekend at the above a few weeks ago. Cycled the Monsal Trail to Bakewell with the boys (9 & 5 yrs old) 8.5 miles each way. They have open the old railway tunnels which makes the route very exiting for the kids.
As for the campsite, it was just purfect. No play area for the kids, but plenty of rabbits hopping about and 3 goats too keep the interest while on the site.
Toilets and Showers the best I've seen and also a place to wash your bike or the Dog