I read in another post that you prefer wooden type ones but my girls (and my boy) have a Fisher Price dolls house. It has seen hours of play. DD1 got it at 18months old. Even my 17monther loves to put the things in and out. It's just open at the back. It has solid chunky pieces but realistic enough that my 7yo still plays with it.

I always planned on getting her a 'better' one, but ours is so loved and so played with I never saw a need, plus it's not ginormous so it's reasonably easy to store.

There are some beautiful open-ish wooden ones around.