I've used a 2 kid trailer like wnyrider used for my 40 border collie. He barely fit in there comfortably He was way too nervous to sit down and the bottom isn't really sturdy. I tried putting in a hunting pillow (round, weather proof and in camo up here) and he didn't like it so I need to figure something out.

I have gotten him in it for one ride - my son's tag-a-long and son were attached to me on the hybrid and the dog in the carrier we attached to the tag-a-long. I was pulling an extra 120 pounds and I felt it We didn't crack 10 miles an hour but we had fun (well, except for the dog) and I felt like a traveling circus because everyone we saw had to come down to the road waving to see the sight!