I remember this movie in I think 1985-1988 it was about a boy and a girl and their mom. They lived in the city but were going to their grandfather's house in the country. Well they get there and after a couple of days they go exploring in the woods to follow a rainbow and they find the end and there is a midget or a leprechaun that they befriend. He takes them into the rainbow and there is this whole other world there with butterfly people and this big blob type thing that lives in a hole. I really enjoyed this movie and would really appreciate it if someone could please help me find title. I really would like to have my kids enjoy this movie too.

I believe your movie is The Great Land of Small, for which we can blame Canada:

https://www.askmehelpdesk.com/movies/boy-girl-have-mother-circus-gymnastic-they-go-185332.html?highlight=great+land+of+small