A mixture Matt recommended.
About a gallon of diesel fuel, a gallon of used engine oil, (which I seem to have an abundance of) and some red newspaper ink. (Matt said a few tablespoon fulls, I made it strong. About 2 cups.)
I put great globs of ink into the bottom of a 5 gallon bucket, poured in the diesel. Not much color change. ( The ink is about as thick as putty. Really nasty, sticky stuff.) Then dumped in the used oil. Instantly turned it black. I thought, is this gonna work? Used a metal paint stir wand thing on a drill set on high speed. Lo and behold it started, slowly, turning a deep red. Absolutely amazing. Used a 3/8 nap paint roller on a pole, dipped in the bucket to apply it. Really nice red on the wood. 2nd coat made it deeper. Got home this evening, it was dry and a deeper red.
I like it. I'll do my big trailer the same next.