@David - I bought a new camper a few months ago so I've been reading a lot of the camper forums lately. 90% of the talk on those forums are sway, being passed by semi's, etc. so I've kinda got it in the brain right now. Semi's pushing travel trailers off the road can happen pretty easily evidently. You should see some of the carnage when those things flip over.
Either way, all the cars mentioned in this thread are far too underpowered anyway. Regardless, of quality, etc.