Name of movie where theres a boy/girl and they go on a picnic and meet a bear, cindy, & ms. teapot, (80s/90s)?

brother/sister go on a picnic in their dream (i think) and meet a bear, a rabbit, a lady named cindy, & ms. teapot. they have their dog BINGO with them...and it rains and they start singing rain rain go away. ALSO it was a children's movie that came out in the 80's or 90's