I'm still of the opinion that the most likely outcome of this mess is that we won't actually leave and we'll have to revoke Article 50 in order to buy some time as the EU won't agree to a temporary extension.
What happens then is anybody's guess but I see no viable alternative to a second referendum unless the quietly let it die off following the Revoke.
I wouldn't 100% rule it a General Election, however, a solution though would very much depend on the numbers for the make up of the new House