Here in Colorado I see guys pulling a travel trailer (not 5th wheel) with a trailer with a side by side or 4wheelers behind it all the time. It’s so common I don’t think twice when I see it. I always wonder what they would do if they ever get caught in a tight spot where they can’t turn around without backing up.
Bumper pull doubles is asking for a pile-up. As far as backing up just drop one trailer and figure it out. But don't pull head in unless you know where you are.