This is a fine hike on a well maintained, albeit busy trail through the forest with views of the Cedar River watershed, Mount Si, Mount Washington, Rattlesnake Lake and Chester Morse Lake.
As soon as you arrive in the parking lot you have a view of Rattlesnake Ledge's sheer rock face across Rattlesnake Lake. At this point it seems amazing to think you will be up there by the end of your hike, but a look at a trail map will reveal some well-engineered switchbacks -- courtesy of many WTA work parties -- that will get you to your destination with less effort than you might expect. The old trail to the summit was in bad shape from heavy use and no maintenance, but WTA work parties helped create this beautiful avenue through second-growth forest to the rocky ledges. In addition to adding a half mile to the old trail, the steepness was lessened a bit.
From the parking lot, walk a short distance around the north end of Rattlesnake Lake to the trailhead on the northwest side of the lake. There you will find porta-potties and a very informative kiosk with maps, trail information and history of the area. To the right is the well signed trailhead. Begin hiking here.
After about a hundred feet you will be met by a "greeter" boulder, the first of many of these mossy monsters you will encounter along the lower section of the trail. As you ascend the trail and gain elevation, there will be a few places where you can look down on Rattlesnake Lake and appreciate your progress. At 1.9 miles you will reach a signed junction; though it is not signed, Rattlesnake Ledge is just to the right, about a hundred yards away.
The ledge is a very exposed, large rock that has sheer cliffs, so it would be wise approach slowly if you are hiking with kids or dogs.
If you wish to extend your trip you can go back to the junction where the sign points out the trail to East Peak 2.4 miles away, or the ridge traverse to Snoqualmie Park, 8.3 miles away. You can also go just a short way from the junction up to Middle Ledge and Upper Ledge which are usually much quieter and afford more sweeping views to the northwest, where you can look down on the crowds at Rattlesnake Ledge.
WTA Pro Tip: Good places to stop for an after-hike social to relax and talk about your just completed hike or other adventures include the North Bend Bar & Grill in North Bend and Stan's Barbecue in Issaquah.