You need to see a NY real estate lawyer for a quick consultation on this. My guess is notices to the Landlord, Neighbor and Real Estate broker are in order to avoid any adverse possession from occurring and to straighten out the landlord's responsibilities to provide that driveway for you. I think it best for you NOT to write such notices yourself. Seems to me your landlord is not aware of a possible duty to mitigate damages.
I am not your lawyer and you are not my client. Free advice here is without recourse and any reliance thereupon is at your sole risk. This is done without compensation as a free public service. I am licensed in IL, MO, TX and I am a Reg. Pat. Atty. so advice in any other jurisdiction is strictly general advice and should be confirmed with an attorney licensed in that jurisdiction.