Was reviewing this thread and realized that I had forgotten to thank you for your last post that did such a nice job of explaining the position you had posted about upthread.I hope this super simplified example helps further explain the effects I described. The Model 3 will have lots of power and it's size and weight will make towing small trailers safe. However, it's rather extreme efficiency, as compared to even a small travel trailer, is atypical and many owners will likely be surprised by these effects.
I've also been reviewing the towing threads in the Model X forum and am becoming somewhat pessimistic about the possible Model 3 towing range. While I expect the 3 to have a battery option that provides a range comparable to the largest battery available on the S in late 2017, @Zoomit has made clear that the maximum 3 range when not towing is likely to be reduced by at least 50% when towing even a smallish camper trailer, and it could be reduced by much more than 50%. In which case it wouldn't be a useful tow vehicle for me, though it still might work for some people.
Since I started this thread I have had the opportunity to see an Alto trailer in person and I really liked it. I refuse to buy an ICE ever again, so now have to figure out how to tow it with a Tesla...