The difference between a Brexit and a Swissit is the difference between a breakup in a
polyamorous relationship and a breakup with a neighbour with whom you share a corridor, but nothing else. Because the former is more emotional than the latter (and you can see how emotional it is with the current Greek crisis and their relationship with Germany while
in the EU), it is unlikely that the rEU (the rest of the EU) will give us the choice of how we would like a future relationship to be, after an acrimonious divorce.
I doubt they would treate us like the Swiss, especially after the Swiss have just shown how fragile the model is in practice.
And do we really want to be like the Norwegians, who get no say in the decision, but must implement it anyway? That will be an even worse situation than now (with apologies to the Norwegians). At least now, we are at the table, even though we can get outvoted. Then we will not be at the table to make the rules, but will still need to implement the rules.
So, there are really only two options, completely in or completely out.
To stay completely in, we will have to accept the freedom of movement principle for EEA citizens.
But freedom of movement for family members is not enshrined in the treaties, but came about because of judicial interpretation and directives issued under the treaties, both of which can be modified without treaty change.
I will therefore argue again, for the purposes of this thread, that the probability of the Surinder Singh route existing in two years time are low, almost approaching negligible. Make your plans for life on the assumption that it will not exist in 2017.