At least one to two days:
33 mile cycle Rim Drive -- a half day to full day,
Cleetwood Cove trail and boat tour to Wizard island -- a half day.
Accommodations
Camping:
There are 2 campgrounds in Crater Lake National Park.
Lost Creek Campground has 16 sites for tents only and is open from mid-Jul to mid-Sep.
Mazama Campground has 200 sites and is open early Jun through mid-Oct.
Reservations are not taken, but generally there are plenty of sites available.
Note - Weather can impact the opening and closing dates of both campgrounds.
Lodges and Hotels:
Inside the park
Crater lake lodge (71 guest rooms, some with lake view) and Mazama village motor inn (40 guest rooms, which is located 7 miles from the rim of Crater Lake in Mazama Village)
are operated by Xanterra Parks & Resorts.
On-line reservation.