Done: The Bird Sisters by Rebecca Rasmussen, 2011, 9781611730883 (large print edition).
Well done but not my style. Another example of where the book description on the flyleaf does a piss poor job of describing the story. This flyleaf mentions several characters and events but misses the point. The whole thing is about family. Family loss, regret and sacrifice. Spoilers await.
Told through Milly and Twiss during their present-day old age and as teenagers in 1947.
Milly and Twiss are 16 and 14 and live in Spring Green, WI in 1947. Their dad is a local golf pro and mom stays at home. Their parents don't get along very well. Dad is obsessed with golf and ingratiating himself with the country club crowd. Mom makes the household work on a shoestring and, coming from a wealthy family, resents her husband's low pay and the snide behavior of the local Sewing Club ladies.
Dad wrecks his car in the river and miraculously survives but his golf game is ruined. Dad starts living in the barn and building a miniature golf course.
Milly is the very pretty and responsible one. Twiss is the wilder, outdoorsy one. Cousin Bett - from Mom's sister - comes to visit. Bett is older, plain looking, and asthmatic. Both sisters look up to Bett. Things happen. Mom makes friends with church organist who dislikes current priest. Past priest purloined parishioners and proceeds and took a powder. Twiss kisses Bett and realizes she is a lesbian. Milly is hot for the teenager who mows the yard. Dad and Mom do not talk much but have the kids send notes back and forth. Dad and Mom make-up and go to a local fair after Twiss fakes a note. Dad says something like "You're wonderful to forgive me." Mom says something like "Huh?" Dad says "For knocking up our niece, Bett."
Things get worse. Milly turns down marriage proposal from Lawn Mower. Milly sends Bett out to talk to Lawn Mower. Everything wraps up back to present day.
1. Even though everything was told through Milly and Twiss I still felt distanced from the more unpleasant parts. The (non-blood related) incest. Milly's longing to have a family but never getting one. Milly choosing to stay with Twiss over escape with Lawn Mower. Milly still loving Lawn Mower and watching closely whenever his granddaughter goes jogging by the farm. The ugly split between Mom and Dad.