"Oh wonderful (dripping sarcasm), another bloody caravan ahead!"
'Caravan' = trailer home/5th wheel kind of thing!
The main difference being it is smaller and light enough to be pulled behind the average family car. But in no way is it even slightly comparible to your versions and it is most definitely NOT an RV! Due to it's lightness of weight, they also have a much slower speed limit imposed upon them, as they are positively dangerous on windy days.
If you don't own one, then it's highly likely you dislike or despise them. Because on our winding, narrow Brit' roads, they can and do cause long delays behind them and are nigh on impossible to pass.
Whilst we're on this subject, we saw a new huge RV, towing an equally huge Hummer on Saturday. There we were craning our necks to see what kind of super human could afford that kind of gas/petrol bill combo'!?