Our motorhome came with the Splendide Washer Dryer which we removed and sold. The unit weighs around 150 lbs, so it will take two people to carry it up the entry stairs, into the bedroom, and to lift it up into the cabinet.
Levering it out of the cabinet was a chore because the space is tight for four hands and the cabinet face forms a lip that you need to avoid damaging. I imagine it will be a chore going in the other direction, also.
It took us about an hour to remove it and carry it out the entry door. Experienced professionals could likely do that part quicker. But, they still need to install a wall vent, connect up the hoses before shoving it into the cabinet, and bolt it down to keep it from shifting. I wouldn't be surprised if they quoted you four hours.
You may be able to save a little bit of money if you remove the two cabinet doors yourself and then reinstall them when the workers are done.
2021 FR3 34DS (V8)
2011 Honda CRV toad