We started at Mowich Lake on July 4th with a plan of camping along the Spray Park Loop Trail. Concerns about making campsite reservations got us up early and to the Carbon River Ranger Station by 8:30am. The rangers were very friendly and it was easy to plan out a loop with an overnight stay at Cataract Valley. Apparently the new reservation system has deterred campers who are worried about not getting to do their desired routes.
The road to Mowich is long and gravel with washboard and potholes, but my little Honda Civic made it up just fine... just plan for at least 45 minutes on gravel unless you have a 4-wheel drive.
The Wonderland trail north out of Mowich Lake was not very well marked, but once we found it, it was a nice jaunt through a forest with views of Mowich shrouded in clouds. About 1 mile out, you come over Ipsut Pass and start a steep talus descent into a valley (overgrown at times). Again, the clouds obscured the view, but we could tell there were massive cliffs overhead and a deep, rich valley below. The hike through the valley was lush and full of forest, overflowing streams and waterfalls. There were plenty of bridges to get you over the bigger streams. We could see freshly fallen trees that had already been cut and cleared off the trail.
The trail is routed over the Carbon River (follow cairns and log bridges) and around a permanently closed portion of the trail. One hiker we passed wasn't aware of the closed trail and had nearly gotten lost looking for it.
The trail continues through the river valley for a bit (bushes were thick here), and then you reach the suspension bridge. Well worth a look! What a feat of engineering! 
We passed the Carbon River campsite and began a grueling ascent up to our campground at Cataract Valley. The trail is not well-graded and very rocky... we were huffing and exhausted after the 1.6 mile ascent from the valley to the campground. 
After all of our concern, we were the ONLY people at the Cataract Valley campground. Perhaps partly because it is in a wooded forest area without a view. We still found it to be a really lovely place to camp, with a sweet creek running in and around the campsites. The bear poles seemed short, but perhaps the bears are short too? The only wildlife we saw were pikas and birds.
Day 2: We began in clouds and start climbing up out of Cataract Valley towards Seattle Park on the Spray Park Trail. The ascent is STEEP and again not well-graded. There are switchbacks as well as areas where you're just trudging up a hill. Then you reach a verdant alpine meadow with streams and wildflowers and it's almost all worth it :) I'm sure the views there are great, but again, all we could see were clouds.
After a sweet jaunt up through the alpine meadow, we started to see some patches of snow. They were not hard to cross and usually marked with cairns. As we climbed higher the patches of snow turned into more like snow fields. Again, it wasn't too difficult to find your way across/over them... just follow the footprints and look for a cairn on the other side. Good boots and poles were helpful, but no need for any snow climbing gear or extra traction. The snow began to subside as we descended into Spray Park. What a lovely meadow! Again, our views were obstructed by clouds, but we could ALMOST imagine what it would be like with the mountain showing herself behind us. Lovely wildflowers.
After Spray Park, there is a STEEP descent into forest. The trail is pretty straightforward after that. Flowing water and forest. Then within a few miles we were back at our car at Mowich Lake. Phew!
I forgot my digital camera, so here are some pics from a disposable film camera.