Describing the Giant Forest of Sequoia National Park is like reading thesaurus entries for "impressive". The forest is awe-inspiring, extraordinary, grand, towering, astounding, staggering, stupefying, stately, and magnificent. Half of the 10 most massive trees on the planet dwell inside the Giant Forest, including the largest (by volume) living thing in the world, General Sherman. The volume of the General Sherman tree is 52,500 cubic feet.
It's hard to conceive how big that is, but let's try. Think of an elephant. That's a big living thing. Now think about a blue whale. The blue whale is so much bigger than an elephant that it's tongue weighs about the same as an elephant. So that's an enormous living thing. Now take 10 blue whales and smash them together. Now you've got about the same volume of living thing as the General Sherman.
But the General Sherman isn't the only reason to visit these beautiful National Parks. There are many wonderful hiking trails you can take through the mountains here, with amazing views to be had. Try the staircase to the top of Moro Rock, which gives you incredible views of the surrounding mountains and valleys. Or, if you've already hiked and feel like relaxing, drive the Kings Canyon Scenic Byway for the best views you can see from your car. The byway mostly follows the river, and has plenty of spots for pulling to the side of the road and taking pictures.
Spring: April - June (Crystal Cove opens in May)
Summer: July - mid-September (most facilities/roads open & most crowded)
Fall: mid-September - November (Crystal Cave closes in late Nov.)
Facilities reduce/close Winter: Nov.- April (some road closures, limited facilities)
Driving directions from many cities: http://www.nps.gov/seki/planyourvisit/driving-directions.htm
From Fresno: Distance: 60 miles Time: 1 hour, 15 minutes
Take CA-180 E to the Big Stump entrance of Kings Canyon National Park.
Highway 180 east from Fresno enters the Grant Grove area of Kings Canyon National Park, then continues 30 miles east to the Cedar Grove area.
Highway 180 ends 6 miles east of Cedar Grove.
Highway 198 enters Sequoia National Park from the southwest via Three Rivers.
There are no roads that cross the mountains west-to-east through the parks.