After doing this for a number of years I thought it a neat thing to time to see how long this 'event' takes.  In order the following was done:

1) bring out pressure hose set at 60 psi

2) extend slide to 'out'  position

3) turn off pump and open faucets to eliminate water pressure in lines

4) take a 1 1/16 socket and open HWH to drain water

5) while this is happening lift up mattress, open my access opening to valves and turn 3 valves to bypass position

6) loosely re-install 1 1/16 nut back in HWH

7) hook up pressure hose to pigtail hose under sink and open the white bypass valve

8) with pressure on, purge water from sink (H+C) and shower (H+C) and toilet (C) 2 times each

9) unhook pressure hose from pigtail hose under sink and close white bypass valve

10) use a total amount of 1 pint rv antifreeze for both sinks, drain shower and on top of toilet lid to keep washer moist

11) put pressure hose away and back on compressor

12) bring slide in

13) put 2 dryer sheets (1 on each end) on floor

Total time was 11 minutes.  Been doing it this way since 2012 with no issues.  The 177 is a great unit, no complaints.   My wife and I enjoy it as much now as when we first brought in home coming across the UP of Michigan during a gargantuan snow storm in March 2011.