The reasons we should have a general election in my opinion are:
1. I don't think the country would trust Cameron to cut the best deal for us.
2. If that sparked a Tory leadership war then whoever wins, say out of Osborne and Johnson, would not have the full backing of the conservative Westminster MPs.
Both the above points will drive for an election, I suspect an election will address your other point about EU legislation through party manifestos.
I think there will be an election between 6 and 12 months after the referendum next Thursday!
There will only be a general election if Tory MPs vote against the government or abstain in a vote of confidence. If the Tories change their leader, following the party rules, and then MPs vote to bring down the government, what would they expect to gain?