I will be visiting my brother in MA for a couple of months during the winder and would like to stay in my "rig". This will be my first winter using my new RV.

I have it fully equipped, but what do I need to do to ensure the plumbing continues to function in freezing temperatures?

You will need heat tape for the water line, you will need to be sure to leave cabinet doors open to allow air to circulate around the water lines inside, and you will need lots of $$$ for the propane you will need to keep warm. Oh and you will need some sort of freeze protection for the drain valves on your holding tanks.