You can find threads on this forum, or the Enlarging forum, on processing large prints - do a search for similar phrases. One method is to use simple troughs, like paper hangers use (you can find them at Lowes, Home Depot, etc) with glue - you "rock" or "see saw" the prints from one end to another, maybe with a helper for this long a piece (processing time will be longer than usual). You can set them on the floor, and they don't take a lot of space. Washing would be another thing, probably would depend on how long they need to last. Do some searches for "processing extra large prints", or processing roll paper. I wouldn't recommend mopping, too hard to keep uniform.
Bob Carnie might have a suggestion for you if he sees this.