I pulled 2 bikes on
SmartTrailer behind our Big Sky for three years and, all in all, it did an admirable job:

We traveled through several states that don't allow double towing and had no issues whatsoever. In fact no one gave us a second look. I think the swivel wheel type trailers are scrutinized less than a conventional trailer when they are behind a 5th wheel.
You do have to be aware of "tail swing" since you're adding at least 6 feet to the end of your 5er. OTOH it is wonderful to be able to back up with the trailer attached.