Since the debate is across party lines it is difficult to put specific plans for an independent UK.
Plus, of course, one can not know for sure how other countries and markets will react, in which direction, and for how long. But we do know we did ok before the EEC, and that no intelligent country is going to want to disrupt it's own economy any more than they need, so it is a reasonable view that things will fairly much continue as near to the present as possible as companies continue to trade with companies that want their products and/or services. All have an incentive to put together any replacement contracts needed so that isn't going to be artificially dragged out.
Markets may hiccup for a short while but the world is as economically valid on exit as it would have been the day previously, so should correct fairly quickly. No one wants to miss opportunities to gather wealth.
I'm wondering what forward planning is feasible and why it should be considered wishful thinking to assume nations the world over have at least a modicum of common sense. The correct process would be not to panic about wild fears and distortions but to deal with a changing marketplace as changes occur, as happens every day already.
As for workers' rights, I still don't see why folk have no trust in a national government's intentions towards workers but are happy to have a higher unelected authority above it telling it what to do. Being in the EU hasn't stopped the Tories stripping away much of the union power leaving workers without reasonable options without jumping through hoops so far, I doubt it would prevent it in the future either.