Sustrans (the charity responsible for the National Cycle Network, amongst other things) are currently looking for volunteers in the local area.
See the Derby recruitment leaflet for more information.
Dan Robertson (the local volunteer co-ordinator) would be happy to explain more about the roles. Contact him on Volunteers-MidsEast@sustrans.org.uk or 07785 27 37 40. Whilst the leaflet gives some ideas for the roles available, there is a wide set of requirements and it is worth speaking with Dan to explain your particular interests and to see how they can best be accommodated.