An interesting point on JR. Parliament makes the laws; the legislature is there to make sure that the law is applied, interpreting where necessary. The JR is asked to rule on whether there should be a commons vote on enacting article 50. If JR says no vote, then we go ahead, but if it insists on a vote, parliament is entitled to ignore the legislature, by amending the act which JR implies would be contravened, or by passing an entirely new act which overrules the JR decision. The snag is that to pass or amend an act there needs to be a vote in parliament. And round we will go again! To quote Sir Thomas More, I trust that I make myself obscure.
Regarding the debate on whether the government should tell parliament what its exit strategy is, of course you don't show your cards to the opposition (either in parliament of the EU). However, I would have thought that the exit strategy is clear...
1) Invoke article 50 in full, breaking all ties and agreements which form part of our membership of the EU. (That's what exit means, although it would appear that many wish not to understand this.)
2) Speedily enact through parliament those things which are under our control so that the status quo continues where we want it to.
3) Negotiate with the EU about anything that we have lost by leaving so that we achieve the best deals we can. This point can start at any stage and doesn't have to wait for the earlier items. We will win some and lose some, but that's what those of us who voted for exit anticipated (or should have anticipated) anyway. At this point we are out with the best deals that are available.
4) Negotiate new trade deals with the rest of the World, including the EU as we see fit. At this point the EU will have come to realise that being bloody minded is not suiting their interests and will probably be approaching us to replace the deals that they have denied us, or looking for new deals.
From this point onwards it is a brave new World and we need to stay one step ahead as we have done throughout history. My only doubt is whether we have the negotiators of the calibre required to achieve this momentous undertaking. History will judge their success or failure.
Per ardua ad astra.