These sno parks that are available for boondocking throughout Oregon are so handy!  Sno park is maintained by the Rogue Snowmobilers.  Free boon docking during off season (May to October). Otherwise you need a permit (November to April).

There is a huge lot that would fit many RVs, easy turnaround and plenty of room to spread out.  It is right on 62 so you'll hear cars go by but traffic was really light in May, and quiets down significantly overnight.  

In mid May there was a ton of snow at Crater Lake but only minimal snow on the ground here, and the weather was cool but not freezing, and was above freezing temps overnight.

There are restrooms and a really nice warming room, with firewood and wall plugs (that I didn't test).  I didn't see any garbage bins (though I didn't look inside the bathrooms).

Zero cell service anywhere in this entire area.  Crater Lake visitor center had good wifi for free though.