Maps from Rand McNally (RMcN) label some of the park roads in Crater Lake National Park as "closed in winter." The National Park Service (NPS) labels the roads "open summer only." Note the difference in meaning: according to RMcN, those roads should be open during spring and fall as well as summer.
On June 14, we learned firsthand at Crater Lake that the NPS is right and RMcN is wrong. The road looping around the east side of the lake was closed, and it wasn't expected to open for at least another week (many of the hiking trails were still closed, too -- I would advise Crater Lake visitors to wait until July).
Incidentally, RMcN and the NPS both say "closed in winter" for the Going-to-the-Sun Road at Glacier National Park. Neither map makes it clear that the road is not open all the way through until sometime in June (parts open earlier).