I think the idea behind the washer dryer in the Host was to use it while on Hookups. Using it for Boondocking doesn't make sense in my opinion.
If I was traveling lots of miles on highways and had the option to stay in RV parks from time to time on laundry day then perhaps. Even then, most RV parks have decent laundry facilities so what are you gaining.
Not to nitpick but are you certain a Host Cascade and an F550 or F600 are the right direction for you? The combined cost is approaching that of an earth roamer and they will be way better suited for OffRoad camping as you seem to anticipate. They might even be a bit shorter helping with tree clearance that an F600 and Cascade will cause. Plus, keep in mind that while the campers are aluminum framed, it doesn't mean that they are built to handle lots of OffRoad jostling all the time. F600s are designed for actual heavy use like delivery trucks or dump trucks. The suspension on it will be rock hard so the camper won't get much give going down rough roads.
That being said, if you do go with the F600 and Cascade, it would be the envy of many as it would be a heck of a nice setup.
