This first come first serve campground is one of my faves.  You can beat the crowds at the state park and nearby Nason Creek by coming to this FF WalkIn campground.  There is a small loop of sites where you can park and the rest are hike in (they all have parking spots assigned at the top on the road tho).

All of the sites are spacious, but 12 seems a little hilly so small tents might be better.  The view of the lake and the mountains is one of the best I have seen.  There is also a hike to another lake right out of the campground.  It's short and strenuous but will worth it for the views.

PRO TIP:  BRING THE BUG SPRAY -- the mosquitos are really bad in this area and you will need all the help you can get!