Last year we stayed at the
Enchanted Rainforest Cottages in Volcano, and had a great time. We were in the Apanene Guest House. It was like being in the middle of the rainforest, surrounded by fern trees and all kinds of birds. The place was very clean, and offered a small kitchen. We had planned to stay 3 nights and return to Kona the night before our flight to Maui. We liked it so much that we decided to stay an extra night and just drive early in the morning.
Volcano is pretty far from Kona, and the roads to get there are dark. You can drive over and back in a day, but it is pretty tiring, and by dusk you usually head back. Staying overnight is a far different experience that is well worth it. It gives you more time to explore the park, and you can go in at night to see the lava flow in the crater from different angles.
I had previously only done day trips, but will now likely try to stay overnight every time. This was one of the highlights of my trip. I recommend exploring the various stops on the Chain of Craters road. It was also fun to drive all the way down to the ocean, to where the road ends because of lava that flowed over it a few years ago.
Some things we liked there:
Hiking around and across the Kilauea-iki crater
Watching the lava lake during the day and at night
Hiking various park trails
Driving down Chain of Craters Road
Visiting Akatsuka Orchid Greenhouse in Volcano
Thai restaurant in "downtown" Volcano
Stop at the bakery in Punalu'u for their malasadas
If the cottages are not available, we've found many good lodging options on vrbo.com. Just look for ones with a lot of good ratings. VRBO is now my go-to resource when I can't stay at a timeshare I like.