You mean two trailers I guess. It's legal in most states but last I checked not in your state of Delaware. Pretty much the entire east coast doesn't allow it.
I wish it were legal in VA. I would love to pull my boat behind a FW camper. My family owns a trailer dealership; they sell horse, stock, flatbed, dump, etc. trailers. The guys that bring the new ones will often tow in from Kansas or Iowa with two. Sometimes they make it without being stopped, sometimes not. In VA if you are stopped you can not move again with both trailers. You must leave on by the side of the road or have someone else come get it. If it were just a ticket I might chance it but there's no way I'm leaving my boat beside the interstate.