When your family wants you around, it is tricky to get time for writing. My kids are grown and out of the house and I still have this issue! My husband likes me nearby, and the kids are either visiting us or we're visiting them on weekends. There just isn't enough time!
When they are around and we're just hanging out, I keep my laptop nearby so I can pick it up when everyone seems occupied. Sometimes I need quiet time, so I usually get that in the mornings. I have a tiny office because I sometimes work from home. Lately, I've been doing it at the sofa.
If my kids were still at home, I would probably write in my bedroom if they were playing, watching TV or taking baths. Depends on their ages, too.
Sometimes the kitchen table works well, because if you have notes or other materials, you can spread out a little. I go there when I want space and a surface instead of a lap.
Not sure if this will help you, but good luck!