In my case, I'm driving a 5000# truck with a 2500# trailer. It's actually more stable in the wind than the truck alone.
But, that doesn't answer your question. Gusty winds with a light trailer could certainly be a problem, I guess; you might try talking to anyone towing kayaks or small sailboats, and see what they have to say. If those aren't available, maybe a landscaper with an empty box trailer?
I suspect you'd find that it would take a serious gust to do much more than a slight course deviation, but that's just a guess.