Villa Birch is a beautiful place and we highly recommend the place, we stayed here for 4 nights and the house has all amenities needed for a comfortable stay. Its location is also very good in the sense you are outside in a secluded quiet area and it just takes 15 minutes by train or 20 minutes driving to be in the city center. There are plenty of options in terms of supermarkets, petrol pumps and a mall with some resturants. I would however recommend to just go to the city centre if you want to eat out. I recommend staying here if you are visting oslo especially with kids.