Windows

It is okay if you want a coating of dirt on everything inside. I have Maxair covers on my vents and do travel with the vents open.

You probably wouldn't do it more than once

We drive with the vents open when we want to cool the trailer down but not the windows. No smells.

Jim

As newbies we were told to close all windows and vents or else the water in the sink traps would be sucked out and we would get bad smells in the rig. Forgot and left a max air covered roof vent open one time but no bad smells. Anyway, we still close everything.

For sure don't leave a back window down! Look at the back of the rig when you get somewhere. Don't want that inside. :(

You can, but they will crank in or out with the vibrations of the wind. If you have a cover (like an Air Max) over your roof vents, you'd do better to leave them open. If you don't have a cover, they too will vibrate in the wind, and eventually crank open or closed.

I've not seen anyone towing their trailers (TT or 5er's or Toads) with windows open.

I once transported a car for my daughter from Indiana to Charleston, SC, and had to leave the sun roof open to get out of the car. Oh my, what a mess when we got there.

Yeah, if you want it real dirty.