Did the Duke of York set up royal colony New Jersey because he felt was too large to govern?

No, the Duke of York did not set up the royal colony of New Jersey because he felt New York was too large to govern. New Jersey was founded in 1664 by a group of English colonists led by Lord Berkeley of Stratton and Sir George Carteret. James, Duke of York (later King James II) did play a role in the establishment of New Jersey, as he granted the land to Berkeley and Carteret in 1664. However, the decision to create New Jersey as a separate colony was not based on the size of New York, but rather on political and economic factors.