Camping trailer

I tow a lot but it's mostly all relatively heavy braked stuff. I am partial to camping and with out the back seats in the Jimny i have accrued enough camping add ons to fill the car. My question is what will use the most fuel? A fully laden Jimny solo or a mostly empty Jimny towing a little unbraked covered trailer maybe 150kg to 200kg total? I know that I have to travel slower when coupled which is going to put the mpg up but i would be travelling for longer so will use more?

If it fits in the car it will always be more efficient to carry everything on one set of wheels. Weight has very little impact on economy but the extra drag of a trailer, even a small one, will always reduce it. With a trailer you also have the increased chance of a breakdown/puncture with tiny little wheels running on tiny wheel bearings, another set of lights to fail, more hassle parking, lower cruising speeds etc.