I would first remove everything you can such as cushions and drawers plus contents of cabinets and storage areas.
Then vacuum from ceiling down to floors and inside every nook and cabinets, all drawers etc. If you can use a HEPA vac you will pick up minute dirt. Clean the filter often for best results.
Next scrub everything clean starting with ceilings, then working your way down so that flooring is last. Clean inside all cabinets and drawers.
Vacuum all cushions, bedding and upholstery.
You can even have carpets and upholstery all steam cleaned if need be.
Wash and dry all pillows or replace.
Measure the bed. Getting a replacement isn't that pricey. Get someone to hold up the mattress while you vacuum underneath it. I was embarrassed to find crackers, hair pins, dog treats and general dirt under mine. No idea how it all got there, but it was there!
My first choice for cleaning is a squirt bottle of plain white vinegar with a tiny drop of Dawn added plus a stack of microfiber cloths. From there I work my way up to stronger stuff if stains or dirt persists.
I am also fond of magic eraser sponges for cleaning bath fixtures, faucets, walls, stove, surrounding areas.
Be sure to give attention to detail around cabinet, drawer and door handles and knobs.
Vinegar will also clean windows inside and out. I typically use two microfiber cloths. One soaked in vinegar and then a dry one to polish.
Finally before closing up the rig, squirt it with Ozium spray. Close the door and let it sit at least an hour. That will kill any leftover germs and give the place a fresh smell of "nothing".
The above method is everything I did to my motorhome before showing it for sale.
I guess I did a great job because it sold in under 48 hours and also later, the new owner was shocked to meet my dog who had traveled for 8 years in the rig. There was zero evidence of doggy use. No damages and absolutely no smell.
