There are quite a few 13' trailers out there that can, with care, be kept under 1500 pounds. It will require going easy on amenities (e.g., using a porta-potty instead of a full bathroom) and packing lightly.
With a smaller tow vehicle and towing close to its limit, there is one often-overlooked amenity you cannot compromise on: electric brakes
on the trailer. Unfortunately, not all small trailers have them.
Best wishes on your "egg hunt"!