Sounds like you've got it. The only thing I can think of that you would do under your bed (I'm assuming that's where your water pump is; I've got a 210WBS and only storage under the bed) would be to make sure that you've got the winterization valve turned so that the water pump draws from your fresh water tank as opposed from the hose that draws the anti-freeze out of the jug... If you turned that valve back after pumping the anti-freeze solution, you don't need to go under there at all.
Maybe someone with a 189FDS will chime in if the above is in error in any way, but, that's all I've ever done with any of my trailers. I use air now instead of anti-freeze, so, I don't ever worry about which direction the pump's draw valve is in.
My 2 cents, your mileage may vary...
2 Cats; J-Lo and Ragamuffin :R
2014 Thor Tuscany 40RX DP
2011 Ram 2500 Longhorn CTD HO
2011 Keystone Cougar 318SAB (now gone)
2008 FunFinder X 210WBS (Sadly gone)