From Corbyns campaign, I think he's made it quite clear that his priorities are (1) get a deal, rather than having the "no deal better than a bad deal" approach, (2) negotiate in a co-operative spirit, rather than the "we'll be a tax haven" approach, (3) secure customs union membership, (4) secure rights of British nationals abroad.
I don't really know what else there is for the man to say, like how much detail are you expecting without him prejudicing their negotiating position?
I think he's made a fairly credible case in the last few TV appearances, personally, and I'm by no means a "Corbynista".
Given the unbelievable complexity of the negotiations, I'd like more than a few bullet points. I'm not saying May is any better btw. I'm 99% sure we'll get to the 2 year point with bugger all negotiated.