A large wildlife book, start to finish, could take one to two years, but then I would expect to get several good (nature) magazine features off the back of this, plus of course a lot of stock.
The important thing isn't the house. It's the ability to make it. You carry that in your brains and in your hands, wherever you go... It's one thing to carry your life wherever you go. Another thing to always go looking for it somewhere else.