I was thinking you should just cover your trailer. And make fold out sides. You could let the side(s) down depending on which way the wind was blowing the rain. I use heavy steel on my smokers, but in a heavy rain depending on how long it goes it messes everything up
Current Smokers: Backyard RF Offset and Hybrid RF Offset trailer rig with Cowboy cooker and fish fryer, always room for more........
onesquin, you're absolutely right. The metal thicknesses between the oil tank and the LP tank are way different. I'm guessing the oil tank is around 1/16" - 3/32" tops.
Rodcrafter, I gave serious thought to making a permanent roof for it. I know it sounds really picky, but I can't design a roof that looks halfway decent. I'm trying to make it as clean looking as possible. I want it to look as good as it cooks. I even gave thought to making a foldable frame with a canvas top, just like a boat bimini top.
I live in a very cold climate (MN) and have never insulated any of my CC or FB's and never ever have had a problem. Last winter we cooked at a comp where the air temp was -22 and the wind chill was -40. YES I said -40. We had no problems with temp what so ever. Don't over think it. In my honest opinion there is no need to insulate to retain temps.
I'm not worried about ambient temps. I'm worried about torrential rain. Which happens a lot here. I can easily lose 100° during a rain, and white smoke will start pouring out of the stacks. That what I'm trying to prevent.
This was helpful along the lines of insulation on the FB. I was going to do that on mine, I live in E. Central Wis. and was worried about not having it. After reading what you just posted CRS, (we have similar temps) (just south of GreenBay), that makes me feel better about skiping the insulation on mine.