Are Grand Canyon, Petrified Forest, and Saguaro NPs open?

I wouldn't make travel plans based on info from strangers on the internet.

From the horse's mouth:

https://www.nps.gov/index.htm

It’s going to be hard for anyone to give you a definitive answer when we don’t know how long this shutdown will last and the NPS website link says it will not be manned with updated info.

From the link given above to the next link: (I stopped after #2.). Good luck.

“Because of the federal government shutdown, www.doi.gov is not being updated and will not be able to respond to inquiries until appropriations are enacted. For more information please visit: https://www.doi.gov/shutdown”

There is also this post if you haven't already seen it:

https://community.ricksteves.com/travel-forum/transportation/traveling-during-a-government-shutdown

Grand Canyon National Park remains open. However, the south rim visitor center is now closed.

The main gate at Saguaro National Park has been closed. The west gate reportedly remains open.

Petrified Forest National Park is “completely closed” according to its Facebook page.

Look at State Parks as an Option. Some may be closed based on seasonal weather conditions.

Regarding the state parks, many have had their budgets cut significantly and are understaffed. If people choose to go to them with the NPS being heavily impacted, they need to set their expectations accordingly.

For me, the unknown wasn't worth the stress. Even though the parks are open now doesn't mean that will be the policy in a week from now. I cancelled our entire trip and have no regrets.

There are two saguaro NP areas. One east of Tucson one west. I believe the west side is simply a drive through area. If you go west from Tucson you will see thousands of saguaros on the way going over the pass.

I believe treemoss is correct re. Saguaro. Its been a while since I've been there. The road thru the west park is public highways. I can't recall if there is a visitor center on that side. There are hiking trails. I would imagine that, in theory, you should have a park pass to park in the lots, but if no one is patrolling. . .Its a beautiful park. The Desert Museum is in that area, too. It is more like a zoo, and is well worth a visit.