Crater Lake is open 24/7 365 days per year, definitely worth the trip.
When the 12,000' top of Mt. Mazama was blasted off 7,700 years ago forming Crater Lake it sent ash into Idaho and Montana. We saw Native American dug-out dwellings dug into Mt. Mazama ash along the Snake River in Idaho.
There may be roads/entrances closed a good part of the year however. Currently 1/3 of the rim drive is open to cars.
Another campground within driving distance of Crater Lake is La Pine State Park. They have pull-throughs up to 90' long.
Here is the current Crater Lake road status:
