The plan was to negotiate an exit with the EU. That was always the plan, has always been the plan and is still the plan.
Leave proclaiming that it was possible for the UK to come to an agreement with the EU is not a plan, it is a statement of what was hoped could be achieved. Negotiation of itself is not a plan, there has to be something being negotiated towards: an end game.
So you must have details of that plan - the Leave plan.
Who formulated it, and was it ever published? Was it the same plan that was supposedly being negotiated by David Davis, Dominic Raab and Stephen Barclay and DExEU or was it May's plan? Or was is some other plan?
The problem for Leave, and thus the country, it that there never was one "end game" to negotiate to. There was Norway or Canada +++ or the Swiss model, or even no-deal, and not one of them could command an agreement all Leavers could live with. So from that we got the blaming of Reminers and the "Will of the people" nonsense.
If the negotiations were to be for the "Will of the people" then one of the many Leave "plans" would have had to have gained 16,141,242 votes. That is the Remain vote +1. If that number could not be achieved then the true "Will of the people" is to Remain.