Had a few comments on FB about the clean return rollers saying that they wouldn't be like that.
Well duh....I'm not finished, but the only way to get the mud behind them without snapping them off was to put the mud on first, then the wheels (and road wheels, drive sprocket and track) and then add in more mud.
BTW, for those wondering how I did the mud, it is half and half, Vallejo Dark Earth Effects and Brown Earth effects, mix the 2 together (I find the dark earth too grey, and brown earth too red, mix together and viola), then added in some Woodland Scenics static grass (don't recall the color), and Woodland fine ballast (again don't remember the color) for some extra chunky texture. Little bit of water as the static grass thickened it up some, then just paint it on in all the nooks and crannies!