This may not be what you wanted to hear, but when I took my Salem out for it's first voyage and it got very muddy, I used my Hoover FloorMate wet vacuum on it. It's my main, #1 cleaning tool for in my house, since I have an old dog with a weak bladder that pees on the kitchen floor daily. That thing cleans the floors really well, the spinning brushes clean textures well, and the fact that you're applying hot, clean water and then the machine is picking it back up (along with the dirt) seems to be a good idea in theory. It's not a cheap solution, but it works.
2015 XLR Hyperlite 30HFS5 (mods being performed regularly)
2009 Salem LA 292fkds (gone)
Nights- ('12)23 ('13)23 ('14)15 ('15)31 ('16)25
2014 Harley Davidson FLHX (XLR cargo)
2014 VW Jetta TDI (diesel sipper, camping support vehicle)
2011 Ram 2500 CC 4X4 CTD, B&W Companion (toy hauler hauler)