I was going to put that in too, but the furore of MP's voting for remain against the previous referendum results would just see the likes of Farage et al getting more traction. To get remain it would have to come from the people, hence the second referendum with remain and no deal as the options. (I would say remain, May's deal, no deal) but that would just lead to Brexiteers claiming that the ballot split the leave vote and favoured remain so isn't viable).
The other potential option is to get an idea of what the public want by putting all the different facets like customs union/freedom of movement etc on a sheet and saying to you want to keep or lose them so the government can actually approach the negotiations with an idea of exactly which bits the people most wanted to keep/lose. But in that scenario I reckon you'd end up with every single option being to keep them and thus we wouldn't actually want to leave any part at all. Plus it'd be pretty complicated to do.