I worked at Sly Park as the Rainbow Camp camphost from early June-mid September and had a fantastic experience. The park itself is gorgeous and well managed while the rangers and hosts are super friendly. Day use areas and day use parking fill up very quickly, especially on weekends, so arrive early if you want a good spot. The hiking trails around the lake are beautiful and easy to traverse. I’m in my mid 40’s and walked the south side waterfall trail from Hazel Creek to the first dam and back in about 3 hours…and I’m by no means a regular hiker. The rangers and camp hosts alike make regular rounds to insure that there is no picnicking/day use or day use parking going on in the numbered camp sites and to make sure the park rules are being followed. Numbered sights are available by reservation only.
Rainbow, Kam Loop, Dogwood and Hazel Creek camping loops are nicely shaded and stay much cooler than the camping loops toward the front of the park but it can be tough to get a larger motorhome or travel trailer into the back of the park. The roads are very narrow with plenty of blind corners. Unsupervised children on bicycles, hikers, and other campers walking dogs on the roads is very common, unfortunately so are speeding cars. Be cautious on the roads and keep a close eye out. There is plenty of potable water spigots available throughout the park and plenty of pit toilets. There is also a lovely, short hike to a waterfall! It’s just a 1 mile walk along the lakeshore from the Hazel Creek day use parking area. I definitely recommend this campground. It does get very busy on weekends, so if you would rather not deal with the “Weekend Warrior” type of campers, book your stay for mid-week (Mon-Thurs) and probably avoid camping in July altogether.