Sleeping porch - I would build in twin-bed size banquettes (with storage, of course) around the sides - of what is essentially a screened porch - and let the kids sleep "outside" in summer and use it for nap space all year.
The Prettiest Porches that Ever Happened: Secrets Revealed
On this Maine cottage's porch, dogs Minnie (left) and Nash get cozy on an iron-and-brass daybed, sporting a vintage seersucker coverlet. The Moroccan rug is from Canvas. Porch and Patio Decorating Ideas - Country Living