Pencil and collage on paper.
I bought a sanding machine for my big woodpanels that I have left from my last project. I painted on wood before but I didn't sand it down, so now the surface is really smooth and that's much better. I used to paint on canvas a lot and although it's a light material it also bounces back and forth if you paint. Wood is stabile and much smoother which will speed up the process.
The bad thing is that it's quite heavy.