Just want to be clear here - there is literally no way this goes on for more than a month or two in its current form.
@Andysol is right on the money here. American defiance will simply not allow it. You can condemn them, judge them, blame them, but people will not remain in their houses for more than a month. Maybe two, if rent freezes and meaningful stimuli are passed.
When that defiance occurs, I expect the parks to follow suit in its wake. The mathematics going into how long we need to stay sequestered don't take into account very real, very human elements, including cabin fever, alcoholism, suicide...