I pulled my friend's daughter in their trailer. 40 pound kid, dunno pounds of trailer, 39x25, and some steep hills. I was actually worried that I'd have to stop because it was so hard.
Then on downhills I was worried I couldn't stop.
Ended up fine, we spun around the neighborhood for a while, but it was pretty hard. I'd get a triple for doing such work, or a mtb.
cdr