Secret treasure

This is not a finished piece, by any means, but I wanted to work some things out on paper before developing a painting of this. 

From my parents house, the lane leads straight out onto the marsh. There is an old abandoned caravan small and round, disappearing into the reeds and the landscape, it was used by model airplane enthusiasts. 
On one of many walks past this last week, I thought I would peer in through open door.
I got a surprise as a swallow skimmed past me and I glimpsed a beautiful 'treasure' nest, a joy that still warms my heart, and so I have used gold to try to convey the magic of this old abandoned caravan and its secret inhabitants.
I love this part of the world, it brings stories into my heart and mind and makes me at peace.