I've done a caravan and a boat. The caravan was on its own in a corner of a field, and a girl was using it for incalls; the punt was as crap as the venue. The boat was in Bristol. It must have been about 25 years ago, back in the street punting days, and the girl was using a houseboat. Can't remember a thing about the girl or the punt.
Also a few times in the back of my van, again back in the street punting days. Top of the multi-storey next to the old Spitalfields market, and also another carpark nearby were good places.