even if too late to chime in. i did a crashed landere from the 40k beginner set and painted it with walmart color place red oxide primer, then went over it with a mid dark brown wash and some lighter brown drybrushing.
i never got picture of it before giving it to the person who wanted it painted but the first thing they said was did it land on mars.
i think the browns i used were apple barrel colors.
good luck.