Not being entirely car-free, and so far lacking a trailer or XtraCycle (thinking about it), I don't have anything of a personal nature to add here. But I did have a question related to the topic.
On one of these forums within the last year, someone posted a picture of someone hauling a refrigerator on a flat trailer behind a bike. Impressive, but I had to think that's fine for flat terrain, but could you dare to try to go either up or downhill with it? What do you all think?