Come Away Home (2005) starring Paul Dooley, Jordan-Claire Green, Martin Mull, Lea Thompson, Thomas Gibson, David Keith
From IMDb: Twelve-year-old Annie Lamm's first day of summer break quickly turns into a disaster. She realizes that her parents have decided not only to fly her to Hilton Head Island during their second honeymoon but also to coerce her into spending half her summer with her 76-year-old Grandpa Donald whom she hardly even knows. The place where Annie is staying, Grandpa's "beautiful house right by the beach", turns out to be a dilapidated and neglected dwelling filled with stored newspapers and dust-covered knickknacks. Nothing edible is in the fridge, and only Big Band and Perry Como records sit by his prehistoric stereo. Annie's summer plans of parties and boys are dashed in an instant. Grandpa's house has no TV, no computer, and a swimming pool halfful of brown, brackish water with turtles living in it. His life consists of napping, doing crosswords and spending time with an old codger named Barney with whom he trades endless tall tales. If there are to be any changes, Annie will have to do them~and she does.
I've seen this a couple of times.