Free trade, and control of our borders. Anything other than that is unacceptable, otherwise Johnson and Farrage have utterly failed. If the EU says no, there has to be a standoff, or we cancel trying to leave.
Let's not beat arround the bush, the majority of voters for the leave campaign did so on the understanding that we would have more control over immigration, and so if this can't be achieved under any circumstances, we have to respond with tough counter negotiations, or the British public have voted for a lost cause.