I thought that this year, in order to improve my mental health and just to help myself feel a bit more balanced/enjoy living in London a bit more, I'd try and regularly get out the city to some rural areas where I can go walks/relax etc. I don't really know the South East at all though, so just wondered if anyone could point out some nice places I could get to easily by train. I live in Brockley, so I guess somewhere I can get to on the train from London Bridge or Waterloo would be good.

Also any suggestions for peaceful places within the M25 would be great too. I've heard that the woodland around Chislehurst is really nice. People go on about Richmond Park and Hampstead Heath but they don't really do much for me- too many people and still feels very 'city' I suppose.