I used to borrow a tandem axle trailer from work every year for halloween. I pulled it with my jeep cherokee with the rear hatch up. I lined each side of it with bales of straw and had a few rules.
1. there always had to be a parent on the trailer.
2. no getting on or off of the trailer while it was moving.
3. no sitting on the bales of stray, I shredded plenty for them to sit on on the bed.
4. we never left our neighborhood and I doubt I ever went over 10 mph with it.
We did this quite a few years and never had any problems, but did have a lot of fun.