Normally I don't camp at KOA's but if you are trying to camp and ALSO do some usual Leavenworth things this is the perfect spot.  It is walking and biking distance from town, right behind the Safeway, and has lots of amenities.  Great place for kids especially there's tons of activities, playground and even a pool.  There are 4 or 5 free activities daily and even a couple for 21+ which I appreciated as a visitor without kids.

We stayed in a tent site and it was small and dusty but had a private trail to the river which totally made up for the more cramped quarters.  Quiet hours were observed and the staff was ultra friendly.  Picked up our propane and filled it for us and everything!

I will definitely go back here during shoulder season and rent a cabin.