Some 2.5million vulnerable people who have been told to 'shield' themselves face being shut inside beyond June.
The roadmap warns a 12-week period - in which these people should not leave their homes at all, even for exercise or shopping - is likely to be extended.
That is despite other people in England being given the freedom to go on unlimited exercise trips and drive to the beach.
The 'shielded' group is people classed as "extremely vulnerable" who have been specifically and directly told to stay at home due to Covid-19.
They received the advice because they have a specific condition that makes them vulnerable. Some are over 70 but not all.
"It is likely that the Government will continue to advise people who are clinically extremely vulnerable to shield beyond June," the document warns.
"Whilst shielding is important to protect individuals from the risk of COVID-19 infection, the Government recognises that it is challenging for people’s wider wellbeing.
"The Government will review carefully the effect on shielded individuals, the services they have had, and what next steps are appropriate."
Broadly the document warns that "much of what is desirable is not yet possible.
"A 'zero risk' approach will not work in these unprecedented times."
The details come in "Our Plan to Rebuild: The UK Government's Covid 19 recovery strategy" which sets out the three-phase approach, starting this week with further lockdown loosening at the start of June and further changes potentially from 4 July.
Writing the forward, Mr Johnson says: "It is not a quick return to 'normality.'
"Nor does it lay out an easy answer. And, inevitably, parts of this plan will adapt as we learn more about the virus.
"But it is a plan that should give the people of the United Kingdom hope.
"It is clear that the only feasible long-term solution lies with a vaccine or drug-based treatment."
Mr Johnson is outlining the plan in detail to MPs this afternoon.
But the document published alongside his address to Parliament warns that changes to the global economy mean we will "not return to normal" after the Covid-19 peak has passed.
On Sunday, Mr Johnson unveiled a "conditional plan" on Sunday evening for easing restrictions in England, saying people could take unlimited exercise outdoors, travel to other places by car and should start going back to work if they cannot work from home.
The guidance sets out in more detail what the Government's plans are, and how they are expected to work in practice.
But Labour leader Sir Keir Starmer accused the Prime Minister of allowing his new lockdown guidelines to start "unravelling" after details were lacking.
