Start at Oaks Wood car park on School Lane, Lower Cambourne, CB23 6BJ. This complete countryside circuit links the nature reserve, Bourn Windmill and the Caxton End part of Bourn. Allow about two and a half hours for the walk and short stops.
Leave through the pedestrian exit at the far end of the car park. Follow the bridleway west across School Lane, past Redgrave Water, then turn into the reserve towards the signed footpath to the mill. Pass the fishing ponds and view the windmill from the public path. Cross Caxton Road carefully and follow the field path down to Bourn Brook. Stay on the north bank until the concrete footbridge, cross into the small field and return over the next footbridge towards Brooklands. Follow Caxton End and the raised footpath beside the ford, then return north across Caxton Road. The field path leads back to the perimeter bridleway; return through Crow Hill and around Lake Ewart to Oaks Wood.
Expect gravel tracks, grass paths, gates and a modest climb over Crow Hill. Field paths can be slippery after rain. The first brook bridge has no side rails; take particular care with children and avoid the brook section during flooding. This route uses footbridges and the raised path, not the ford. Keep dogs on a lead throughout the reserve and beside livestock.
Oaks Wood car park opens by 9am and locks at 8pm during British Summer Time or 5pm in winter. Return before the gates close. Parking at the Wildlife Trust office is for staff and business visitors only. The mill exterior can be seen at any time; interior access and its toilet are available on advertised open days. Shops and refreshments are in Cambourne.
Route follows the long Bourn Windmill walk published by Cambridge Past, Present & Future, with reserve access information from the Wildlife Trust for Beds, Cambs & Northants.