Glad you’re making the trip up! Crater Lake is absolutely worth the visit in the off-season. Some winters, it’s still covered in snow in March and April, but this year, it’s very manageable. The closest true town to Crater Lake is Prospect, Oregon, which has lodging options. We love the Prospect Historic Hotel for an B&B option, or nearby in Union Creek, the Union Creek Resort offers rustic cabins in a wooded setting. Either way, be sure to stop by Beckie’s Cafe for homemade berry pie!
There are also options to stay at Crater Lake National Park. Crater Lake Lodge is the quintessential lodge experience, and in the off-season, you may even get a reservation (it fills up fast in summer). Nearby, the cabins at Mazama offer additional lodging, but bear in mind that this area of the park does not have lake views, and may not be open.
Otherwise, another good option for you is staying in Ashland and commuting up to the park for the day (about a two-hour drive, with nice stops for hikes around Union Creek). Ashland has wonderful dining and shopping, and a fun, vibrant arts scene. I’d be happy to recommend lodging here if you’d be interested.