We went camping in Lassen Volcanic National Park.
It is a very wild beautiful place. Meadows covered in wildflowers that look like they are out of faery tales , peaks covered in snow, geo thermal vents with steam coming out, conifers and streams everywhere. It's hot during the day and very cold at night. Bring a good sleeping bag!
The lakes are crystal clear and cold but we all swam even baby girl.
In short, highly recommended if you don't mind some incomfort :)