No matter where you have your desk, even in your bedroom, there will be times that family members just have to interrupt your train of thought - "I want a cookie", "Where are the car keys", and so on and so forth. Working at home is a challenge in itself; you must be very disciplined if you are going to get anything done at all, then with family interrupting, the challenges are even greater.
There is a way you can change this at least partially. All you need to do is to install remote control curtains around your office area. You may not feel like you have much room, but when you need to be left alone, just use your remote control and close the curtains. At other times, when you are not deep in thought, you can open the curtains.
Once you have the curtains installed, your family will learn the boundaries except in emergencies and let you work so you can quickly finish your work for the day and then play catch, watch a movie, or take the family out for dinner.
Before installing the curtains, you will want to make sure that you chosen an area of the room that is certainly out of the way, will not interfere with the flow of the home, and ensure the curtains you choose does not clash with the décor, or your wife will certainly be very unhappy. There is a way to compromise, so you can actually go to work in your home office, and the answer is remote control curtains.