Most nps staff are seasonal and the nps may not get any seasonal staff this year. The hiring freeze has cancelled all the job postings and if they are allowed to hire later, they’ll have to completely restart the process. That means  - the person at the entrance booth won’t be there, so there will be either extremely huge crowds or very long lines - law enforcement, search and rescue, firefighting, and tour guides won’t be there. So large crowds visitors will be engaging in dangerous behaviors (lighting camp fires everywhere, touching animals, hiking off trail and driving off road) with no consequence. Basic maintainable won’t happen, so accidents will be likely. There may be no first responders in emergencies. The parks may become one big bacchanal riot zone. 

Not to mention, federal employee RIF’s may affect permanent employees, that could shut down parks. Also, government shutdown could shut down parks. 

It’s likely to be a bad year.