Crater Lake Oregon
Crater Lake National Park is located in South Central Oregon and is an exciting place to visit. I will say, it gets a little crowded in the Summer, but late Spring (early Spring is still snowy) and late Fall are beautiful. Not only do you have the lake to enjoy, but if you travel around the rim, you will be surprised by all of the sites.
For you campers, there is a good sized campground there for you to enjoy.