Normal range for a
Blackhawk is about 360 miles, but this one had to have had an extended range kit on it in order to have made the flight from Boulder, which boosts its max range to over 1,300 miles. Assuming they started the day with full tanks they could easily make the trip to LA from
Fort Irwin, even after several hours in the air during the fight for the base.
Of course, they wouldn't necessarily know where to go next, unless they had radio contact with the
Pelican.
One other place the survivors could find replacement Blackhawks, that S-Mart parking lot in Colorado at the "Evergreen turnoff by 70". That's where all the helicopters that survived Boulder landed. They'd need to bring fuel.