martian
which bit of Derbyshire are you in?
Our 3 boys love the Mam Tor (we call it the broken road).
We park at the top. On a good sunny day there's usually people there para and hang gliding. Take a pignic.
They love scrambling around. Usually, we then drive down the stunning Winnets Pass, turn left at the bottom and park at the other end of the Mam Tor road, just near a cave. It's great if it's been raining, there's some puddles and if really wet a waterfall to splash in. With our unpredictable weather you can't tell!! Take towels, change of clothes & wellies.
If you have a bit of cash, there's Speedwell cavern (back up Winnets Pass), or the Devil's a**e, Peak Cavern. There's Peveril Castle, run by English Heritage, 11.70 for 2 adults & 3 kids, saving you 90p.
Also nearby is Buxton, with Pooles Cavern, there's a Go Ape next door, not sure what age yours are.
Also, there's a folly to walk up to on the hill nearby. Great fun for chucking parachuted soldiers off! Toy ones, I hasten to add.....
Bon Chance!