Fender mounting methods

Going to start to finish this project soon. As far as fenders I am thinking of just attaching the fenders to some strong trim (Doug Fir) attached to the TD sides. I don't know if I really need to put in metal brackets. The fenders are 13" steel from etrailer which I have primed and painted. What do you all think? Has anyone just bolted their fenders along the inside edge to the body successfully? Referencing last fall's photo of the fenderless TD (below), I was thinking of maybe a couple of through bolts on the 2x2 steel frame (black horizontal area below the wood siding) and then the top would just be attached to the body. The wall in that area is solid wood. A trim board will be mounted front to back to hide the frame underneath. It will be fender shaped in that area to act as a shim to bring the mounting point out from the body about 3/4" to 1".
