Riber Zoo has been closed for quite a while ago. Darwin Forest on the moors above Darley Dale is good place to stay (make sure that lock your bikes up as one was nicked a few weeks ago) – about 10 mins from Chesterfield has indoor play area and a fitness centre. There a few interesting routes that you can join plus there is a farm park a matter of a few minutes away, ideal for Matlock, Chesvegas, Chatsworth, Haddon, Bakewell, Peak Rail etc