Possible title that I remember is Rebecca’s Island. The plot is as follows:
Mother and young daughter flee an abusive or unhappy marriage. They move to the grandmother’s home I believe. She lives with a lake behind the house and Rebecca paddles a canoe to a small island in the middle of the lake. She makes the island her sort of getaway from the troubles of her home life, paddling to the island on a daily basis. There is an ominous feeling to strange people showing up. Maybe the people are looking to find the mother and daughter for the abusive husband/father.
This was read to my elementary school class maybe in the mid to late 1980s. I got the flu and was not in school to learn how the book ended.
Perhaps ‘Becky’s Island’ by Elisabeth Ogilvie, pub 1961?
Vicky mostly keeps to herself. During one of her lone ventures in a dory, she discovers two abandoned and scared children on a deserted island. Vicky returns the children to their home on Becky’s Island, a place rumored to be inhabited by convicts and crazy people. Vicky believes that her good deed is a one-time occurrence, but…
Possibly ‘Megan’s Island’ by Willo Davis Roberts?
Ok. I just returned to this. I believe it is Megan’s Island. I’m ordering it on Amazon not. I have been searching for this book for so long. Decades. It’s comical that I was 100% certain the name was Rebecca. I am unreasonably happy right now. Thanks for the info!
Megan’s Island, by Willo Davis Roberts.
Details don’t entirely match but this might be Megan’s Island by Willo Davis Roberts.