What sounds could represent bright, happy, joyful, youthful, naturalness?
What's the context?
Children laughing comes to mind.
It can also be subliminally placed in the ambiences you choose. An ambience with lighter wind and happy birds for example. A happy news story playing in the background instead of a gloomy one. The kids laughing and playing outside next door. Etc. etc. etc., the list can go on.
I think I can help more if I know what context you have.
Try playing with contrasts.
Make the house with the old lady sound scary. Creaky floorboards, a little bit of scary wind, the house settling in the wind. A couple of dark drones / room tones to make a general feeling of being uncomfortable. Lots of reverb would also make the house more disturbing.
Make the field light, with a few birds, bees, crickets. Light gusts of wind in the waving grass (foley?). Like the feeling of lying in a field on a summer day and just listening to the wind and nature around you.
You can even take elements from the happy world and use them as transitions, like letting the light wind in the field turn into a gust and a shudder in the old lady's house. Or use crickets or insects as transition, where it goes from a natural lightness to something evil, crawling, scraping somewhere....