Total distance is 27.6 miles. Total elevation 5,130 ft southbound. 5,870 ft northbound.
Going southbound you save 740 feet of elevation gain. You also enjoy the more gradual climb up from Bumping River\Fish Lake. Northbound you get to look at Mt Rainier.
Since this section is only 27 miles long splitting it up would not be worth it. For some people this entire section is a day hike. But if you did, then Laughingwater Creek Trail would be a good option. That trail is entirely inside Mount Rainier National Park, so a backcountry permit will be required for any camping. It's 7.23 miles long and drops 3,871 ft from the trail to highway 410. From there its only 16 miles to White Pass.
The north half of this section is on steep slopes so you may want to avoid snow. The south half of this section has hundreds of lakes and ponds so bugs might be bad in the spring. You may choose to go late in the season when snow will be gone, bugs will be reduced, but there will still be plenty of drinking water.
You have a couple options on how you start this section. You can start from the Chinook Pass parking lot, on the east side of the ridge, and hike south over the pedestrian bridge over SR410, then take the PCT which passes the NE side of Naches Peak.
Or you can start from Tipsoo Lake, on the west side of the ridge, cross the surface of SR410, and take the Naches Peak Loop Trail which passes the SW side of Naches Peak. Both routes converge after 1.75 miles. Naches Peak is almost perfectly due east of Mt Rainier and offers one of the best views of Mt Rainier which is only 10 miles away. If you are walking Northbound, then I would strongly encourage you to take the Loop Trail so you are looking at Rainier as you hike. Even if you are going southbound, I’d still recommend going that way. You’ll just have to turn around every so often to take in the view.
All the mileage below is measured from the Chinook Pass parking lot.
[0 miles] For the first five miles you only need to carry water for 1-2 miles.
[1.75 miles] There is a vista just a few yards west of where the trails intersect, where you can look down on Dewey Lake. At that vista you have line-of-sight to a mobile phone tower in Packwood WA, which is S/SW.
[2.90 miles] From where the trails intersect it’s a 704 ft drop down to the creek that connects Little Dewey Lake to Big Dewey Lake. Both lakes have great campsites, so this is a good hike to begin with a short first day. There is an especially cool camping option near here.
When you leave the lakes, you do not need much water. There will be water in 2 miles for sure and likely in 1.2 miles.
[4.53 miles] East of Dewey Peak is a small creek that often flows year-round. If its dry, there’s water in 0.5 miles.
[5.19 miles] Just north of Anderson Lake you will enter Mt Rainier National Park. Anderson Lake is a tiny lake but offers year-round water. You may not camp at the lake, but there is a site just a few yards east of it on the park border. Here you should plan your next water source. If you do not want to go off trail to get water then you need at least 7 miles of water. Just south of Anderson Lake is the best, closest view of Mt Rainier on the entire PCT.
[6.47 miles] Intersection with American Lake. 0.63 miles side trail one way, 186 ft. This is a small, pretty, and heavily visited lake. Cougar Lake is a pretty lake but its over 1,000 ft below the PCT. The loop trail to Cougar Lake is 4.28 miles long.
[8.95 miles] Two Lakes 0.31 miles side trail one way, 192 feet.
[10.5 miles] Shortly after you pass the intersection with Laughingwater Creek Trail you will reach the high point before the drop down to Bumping River. That high point is where you exit Mt Rainier National Park and enter the William O. Douglass Wilderness.
[11.4 miles] 0.3 miles after the sharp switchback, when you come close to the first lake, you can decide if you want to drop down there. Crag Lake has an access trail and camp sites but it’s not especially pretty. Buck Lake is the lake below Crag Lake. If you just need water, get it when the trail crosses the outlet of Craig Lake at about 4,800 ft.
[14.7 miles] Cross Bumping River and gather water for the climb ahead of you. You only need water for one mile. Or get 5-6 miles of water so you don’t need to stop again.
[15.8 miles] When you cross a bridge over the creek you have a year-round water option. Here you are entering the open swampy area that will last for the next 6 miles. It’s a different landscape covered with hundreds of small shallow ponds.
[17.4 miles] Intersection to Twin Sisters Trail to Twin Sisters Lakes. This is a side trip off the PCT. It’s 1.74 miles one way to the spot I like, with 346 ft of elevation gain. I think the best place to camp is on the high ground between the two lakes. It gives you a view of Mt Rainier and puts you near the better shoreline for swimming.
[20.8 miles] Pipe Lake is a good place to get water. You’ll need water for 5 miles to Deer Lake, or water for 7 miles to White Pass.
[21.9 miles] You will cross over the Beusch Lake outlet. In the late spring this “lake” dries up and becomes a creek. There will probably be water here, but not always in the late summer. Here is where you leave the swampy landscape and begin climbing to higher rocky ground.
[23.5 miles] After you pass the intersection with Cortright Trail, you will rise up to the high point (5,600 ft). From here it’s all downhill to White Pass.
[25.5 miles] Deer Lake is a cute lake. If I needed a swim before the trail ends, I would probably do it here and not at Leech Lake.
[26.7 miles] You probably won’t have any mobile phone signal until you are due north of White Pass and can see the bottom of the chairlifts. That will be after you passed the intersection with Dark Meadows Trail. The tower is low and to your right, west of the Kraker Barrel.
[27 miles] If you want to go directly to the Kraker Barrel (gas station and convenience store) and the Hotel, there is a dirt road that offers a direct route. That road starts above Leech Lake. You can also get there from the trailhead by taking a dirt road that runs between the south side of Leech lake and the highway.