Photo taken under working lights - stage lights not on.
With a "captive" audience sitting on chairs on the flat floor of the assembly/dining hall you know that everyone is on the same eyeline/horizon line. This means that I was able to continue the "path" on the backcloth onto the left wing. Trouble is when a member of the cast enters from behind that wing the illusion is broken. But then I suspect the audience is aware this is only a painting in any case!

The audience eyeline is about one foot six above the stage floor. But the Producer wanted a stream in the painting and in order to show the water I had to put the stream arriving from quite high up the cloth. (Note how I continued it on the left wing) So in order to "explain" this apparent sloping stream I really needed to have put in a waterfall just in front of the bridge. But time is a problem and one can keep fiddling about with a painting for ever. "A painting is never finished - it's always abandoned"

Misty clouds across the mountains were done with a very dry brush of white. And a handy damp rag in case I applied too much "mist" and the mountain disappeared.

Design note. Notice how so many lines (Mountains; branches, distant trees etc) all converge on the central focal point of the bridge. The bridge was also painted with much darker colours.

I wanted lots of meadow flowers in this scene so enlisted the help of the "Reception" class of four year olds. Split up into pairs they were each given a colour and an area in which to put dots and splurges. Most noticeable in the top photo at the bottom of the two foreground trees.

And very well they did too.

Incidentally the moral of this is not to be too fiddly when painting a backcloth. The audience is too far away to see detail. So for flowers in the distance- dots will do.