Warning signs arethere to protect you, your pets, and to preserve the park for future visitors. Please obey them. There was a lot of snow here when I last visited. Be aware of your surroundings there are bears, cougars, and rattlesnakes here; and a protozoan called "Giardia Lamblia" in the water which can make you sick (so treat the water before drinking). The roads are narrow and winding so please obey the speed limits. Also pay close attention to the weather.
Gas stations and stores are few and far between in Kings Canyon National Park. Fill up at the facilities near Grant Grove. Your cellphone will not work in most areas of the park if you try to call for help if you run out of gas.
These are some of the toughest national park roads. The King's Canyon highway and many of the side roads contain a 5-8% grade. This may not bother native Californians who insist on making you pull over, or if there is no turnout available, will aggressively tailgate your vehicle suggesting that you should drive your car off the road entirely, but for those who want to actually see the parks, put your car in a lower gear while driving downhill. This will tick off the Californians, but it will save your breaks.
I noticed when I got to the area where the campsites are (at the bottom of the Canyon) that there were a lot of Rangers. Don't speed or you will have a ticket!
Keep your food locked up in the areas provided by the Park. Don't startle a bear. Make noise on the trail.