The two derelict cabins were constructed of walnut dyed cotton.
A good jumping off point but they were pale and lacked the weathered look.
I had a number of choices for changing their tone from paints, dyes, crayons, ink pencils to drawing markers.
My husband scours the internet (Amazon) and I have received many variations of 'colouring sticks'. Some are dedicated for cloth and are colourfast with treatment but others are just a mystery. As this piece will probably not be exposed to either water or intense light, I decided to give this brand, Hethrone, a spin. It was also the simplest, easiest to use and ready, at hand.
This brand is sold as a water soluble drawing pen/brush.
I do like how they worked on the fabric. It wouldn't be too much trouble to make them semi permanent with a fabric treatment.
At this point I'm not considering it.
Now my soft brown walnut fabric has some strength while looking closer to a cabin hidden and forgotten. Also this darker colour will stand up to the intense yellow and oranges that are coming.