What could connect Hampstead Heath and West Croydon? Well, it is the new London Overground orbital line which is nearing completion, with the final section due to open by the end of this year.
Here are three top days in lovely parks on the new line - hop on and off using Oyster. With the Victoria line connecting to the Overground at Highbury and Islington, north and south London have never been so close.
1. Hampstead Heath. Of course. The station (cunningly called Hampstead Heath) is about two minutes from the Heath, with its swimming ponds, walks, wonderful views from Parliament Hill across London and Kenwood. Walk on to Highgate Cemetery and get the bus down into Camden.
2. Crystal Palace. Dominated by the really rather lovely park, home of the famously and delightfully inaccurate dinosaurs and sports stadium. Hilly, with nooks and crannies as well as open spaces, it's worth a visit. The Green Chain Walk can be picked up here too, to Beckenham Place Park or Dulwich Park. Some nice little cafes and shops too.
3. Richmond. Hard to beat. Take a bus from outside Richmond station up to the Richmond Gate, have coffee and cake at the Pembroke Lodge cafe, and walk through the wilder wooded bits, as well as the Isabella Plantation. Walk down through the meadows, out of Petersham Gate, and follow the footpath signs to walk back into Richmond along the river.