Thanks for all the feedback.
The box is an after market add on, so that was the concern. It wasnt made with it.
We had a camping trip close to home already planned when we discovered the cement under the trailer. We opted to take out all but 160 lbs and load it accordingly. We also didn't load the box up super heavy. We camp fairly close to home usually, so we weren't too worried. It towed great that way.
We have plans of getting to a weigh station to check the weight and look at taking the 160 lbs out and putting a more useful weight there.
