I think the only way we can re-join is by holding another referendum and that would be political suicide for any party who proposed it. It would also galvanise the leave vote as they would feel that the democratic mandate achieved at the last referendum was being undermined. That could have serious ramifications for the UK political system especially as faith in our democracy has plummeted over the last few years. No party would risk taking us back into the EU without a democratic mandate that expressed the mythical "will of the people"
The re-join campaign would have to be honest and tell people that there would be every chance we would have to accept the Euro, freedom of movement, join Schengen, be at the behest of the ECB and play a full part in the Capitalist construct that will perhaps one day lead to an EU state and the watering down of British democracy to what would be possibly be at best a regional tier of government.
On the other side the "Stay out" campaign would have to justify their record which since Brexit has been pretty appalling due the gross mismanagement of this idiotic government.
It is a dangerous endeavour and could end badly as I fear the Far Right would be enhanced by a re-join victory and a country already divided would be divided even more.