This may be a bit of an optimistic take, but there's at least some evidence the IFR is ~0.37%. Given the current number of deaths in NYC, that would imply at least ~20% of the city population has already been infected, likely more given the lag between infection and death. If that's true, the best strategy will probably be to keep vulnerable groups isolated and loosen some restrictions until herd immunity is reached. How long that would be depends on the hospitalization rate since ideally we'd have hospitals just barely at max capacity, but I don't think its implausible by the end of the summer we'd reach ~75% infected at which point all restrictions could be lifted.