We used to keep turtles as pets.  They like a lot of the same things that ducks and chickens like.  They really liked meal worms, grapes, melons, kale, mustard greens, water softened cat/dog kibble.  Their absolute favorite was strawberries.  They need a diet that's 50% protein and 50% veggies/fruit, heavier on the veggies.  An unfinished basement is a good place for a turtle and they definitely do prefer to sleep under things.  We made them a small wooden 3 sided box that we put upside down.  Most turtles hibernate from October until late Spring (early May here).  I love turtles.