It is usually a waste of time to build a doghouse for a Maremma. Each wants to chose its own place, which will be a place where it can watch all entrances to its property. All it needs outside is a shelter from rain and shade. It is sensible about heat. No amount of cold bothers it if it has a little protection from the wind.
Puppies grow best if they can move freely.
Grown dogs require less exercise. If you live in a city or in the suburbs, exercising should be done on a lead. Maremmas are still generally sturdy and healthy dogs. They require the usual preventive shots for distempter, hepatitis, leptospirosis, parainfluenza, and parvo, with yearly boosters. Rabies shots are also required in all states.