There are ample spaces at the hike's designated parking lot, but you'll need to buy a recreation pass (for $5 per day) before setting off. Once on trail the gradient is remarkably consistent, and there are no significant obstacles at all. The trail builders really have done an exceptional job with this one, and their skill in making such an easy-to-hike line is amazing.
The trail starts out in typically dense Cascades forests, and as you climb the trees thin out and give way to barren alpine tundra. Each stage of the hike is wonderful but the upper section really is utterly staggering, with the views opening up all around you and the Cascades disappearing off into the distance.
Cutthroat Pass is on the Pacific Crest Trail (which goes all the way from the Mexican Border to Manning Park in BC) and if you're doing this hike in late August or early September you might see some thru-hikers in the latter stages of their trip. Regardless, the natural scenery is fabulous enough, and the interest of potentially meeting a PCTer or 2 only adds to the thrill of the hike.
Cutthroat Lake is also a spectacular spot and well worth detouring to. For those brave souls who want to swim in the lake, the rocky area around the lake's southernmost tip is the best spot....!