We used the awning hook to hold up the flexible ducting when reinstalling our washer, then Steve reached down (2 person job). If they just let it droop, you'll get a lot of lint/condensation/a clog so do inspect through that opening when they're done.
Here's a view from the top looking down the back of ours after the reinstall. We added the foam pipe insulation, it wasn't original.

Michelle
How did you get that photo when the shelf above the washer is stationary.
I have no room at all to work behind the washer.
Can you remove the washer without removing the flex vent hose?
Steve removed the "box" at the upper rear corner of the shelf (at least that's where it is in our coach). That gives access to the hoses, etc. The photo was taken looking through the opening after the "box" was removed.
You can pull the washer forward with the vent hose connected, but I can't remember if it can come all the way out and onto the floor without disconnecting. Our vent host length is about the height of that cabinet.

Michelle
I replaced the door switch today. Once the washer was out and the top removed you just remove the 2 screws holding the door switch from the front of the opened door.
I did not have to worry about the dryer vent hose because there wasn't any like yours is. The washer just backed up to a piece of pvc coming back from the outside vent. :o
We had ours upgraded from the original unit to the 2100XC in 2008 and the install was done by CW in Denton, TX. I guess they added the flex hose....
-M