If you've not been then Malham Cove is great, there is an afternoon walk to the Cove, up to the Tarn, then to Gordale Scar. About 6 miles iirc, spectacular views. Also good is Brimham Rocks, a strange collection of rocks that look like a giant's sandpit. Kids love it and so do I for climbing. Settle is a nice market town and not up itself about it, it's just a working town. The 3 Peaks is a tough day out for the fit.
Other than that consult the tourist office, they know what people want when they visit the place. Have fun. It won't be the first and last trip.