… NPS also lagged this year in staffing up for the busy summer season — a monthslong process that begins during the winter — due to the Trump administration’s hiring freeze. … Yosemite ultimately hired 25 fewer seasonal employees this year compared with last because of the hiring delay, according to the person familiar with the park’s staffing data. … Jobs running the park’s water treatment and electrical systems are particularly challenging to keep filled in the remote region, they said.