This 29.8 mile section is beautiful but can be discouraging because the middle is lower than either trail head. That low point is the bridge over Brush Creek.
There is no mobile phone service anywhere near the trail head or anywhere along the trail.† Driving eastbound on SR20 you will lose service half way along Gorge Lake.
[0 miles] Going northbound from the trailhead on the east side of Rainy Pass, the trail starts with a 5 mile climb up the Porcupine Creek valley to Cutthroat Pass.
[2 miles] While the water at 6,000 ft is fairly reliable, 1.4 miles ahead, to be safe you may want to fill up on water at the Porcupine Creek crossing. You will want water for at least 7-8 miles.
[5 miles] The slope is not too bad thanks to five switchbacks just before the pass.† At Cutthroat Pass the PCT intersects with the Cutthroat Pass Trail which descends rapidly to Cutthroat Lake witch you can see below to the east.†
[6.4 miles] From there you will traverse the mountain for 1.4 miles to the second highest point in this section (no name), where you will leave the day hikers behind.† And from there descend 700 ft north to Granite Pass.†
[7.5 miles] The 2.9 miles from Granite Pass to Methow Pass has minimal elevation change and follows the Swamp Creek valley.
[9.5 miles] A nice side trip is the 0.8 miles and 634 ft to Snowy Lake. You may also find water at that trail intersection.†
[10.5 miles] From Methow Pass itís a consistent drop over 8 miles losing 2,263 ft. as you follow the West Fork Methow River valley.† There should be many water options north of Methow Pass, with increasing flow until you cross the WF Methow River bridge.† Only carry the water you need to get to the Bush Creek Bridge.†
[18 miles] Brush Creek Bridge is 590 ft lower than the east trailhead at Rainy Pass.† Fill up on water here. There is only one other water option before Harts Pass.† That is 5 miles away and is not 100% reliable.
The 5.18 mile climb to Grasshopper Pass has a fairly consistent slope of 535 fpm.† You can split that climb if you camp at the Glacier Pass campsites.
[24.5 miles] After you pass the east ridge of the south peak of Syncline Mountain you will find a small valley with a patch of green grass.† There is a spring there that is fairly reliable. If you don't find water within 0.2 miles of the trail, then there is none. East of the spring valley, out to the small ridge, is a popular camp area with a lot of space. Harts Pass is 6 miles away.
[26.5 miles] The highest point on this section is on the east ridge of Tatie Peak as you walk toward Cone Mountain.†
[28.5 miles] After you've walked the 270 degrees around Cone Mountain you will approach the Brown Bear Trailhead and road route to Meadows Campground and Harts Pass.† If you plan to camp at Meadows Campground, you may choose to leave the PCT here.
When you are at the intersection with the short path to the Brown Bear Trailhead you may notice two other trails, one going west and the other going south.† The trail to the west is an old road that will take you to the Brown Bear Mine less than 1/4 mile away.† The trail to the south will take you to the remains of the old mine camp, also less than 1/4 mile away.
[29 miles] The last mile of the trail to Harts Pass has a nice western exposure for viewing the setting sun, before it curves back east to meet Harts Pass in the last half mile.
There is no running water* (caveat below). Trailers are prohibited. Vault toilet. Two bear lockers (near the ranger station which is usually closed). The campground has 5 sites and does not take reservations. It's $10 per night, $15 if you have two vehicles.
The road that heads south goes to Meadows Campground 1 mile away where there is another vault toilet and 14 camp sites, also no reservations, same price. That road continues to the Brown Bear Trailhead, 1.7 miles away.
* Unreliable water near Harts pass. 0.38 miles northbound from the trailhead there is a trickle stream that crosses the trail here 48.72417, -120.66439. You may be able to collect water there.
The road to Harts Pass is 10 miles from River Bend Campground. It climbs 4,200 ft on a dirt and gravel road with no rail. The upper half of the road is easy. The lower half has boulders and sheer drop-offs (like the 850 ft drop off at Deadhorse Point). Instead of driving it yourself, you might either hitch up, or get a ride from the Lion's Den. The road from Mazama is paved up to the Lost River Bridge.