Hello OP!
Stayed in Japan for a while, Stay is going to be really expensive considering you’re going with your family (and would need a basic-good room).
-Commute is manageable wrt expenses
-Get down in Haneda airport as it is closer to Tokyo
-Google maps is reliable, but not precise.
-You’ll have to walk a lot! Please make sure you get a really good-comfy shoes
-Always carry a bag for disposal of waste, Japan does not have dustbin-concept.
Would be able to estimate expenses for you If you have any itinerary in mind, which places you’d like to visit etc.
Roughly speaking, Hotel stay would be around 5-6k per day according to location (but very basic rooms).