I would get your levels checked before you supplement with high doses. I was taking 2,000 during my pregnancy and found that my levels were way too high. And FWIW - I live in the NE. Spend minimal time outside and when I am outside, I am wearing longsleeves - even in the summer.
I live in NJ & my pedi says she has NEVER had a baby with Rickets(the disese you get from lack of Vit D) in her practice.
Additional info from the Mayo Clinic:
"The major biologic function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones. Recently, research also suggests vitamin D may provide protection from osteoporosis, hypertension (high blood pressure), cancer, and several autoimmune diseases."
I don't worry too much about vitamin D supplements in the summer when we get outside every day, but it becomes more of a concern as the days get shorter, colder, and cloudier in my little corner of the world.