The previous post has it down, the only item I might suggest is you can use a half cup of household bleach in the fresh water tank after you drain everything, let set for a day or so, drain, and refill with fresh water. You might consider filling up the black and grey tank as well, and draining them, just to get rid of any odors that may occur when you flush the toilet.
Scot & Laura Kellersberger
2001 Newmar 4 wheel drive Dutch Star 3891, 2005 GMC Canyon. Demco Tow Bar & Baseplate U.S.Army (ret) 1985 - 2006