Thalia's Enchanted forest is a great place to stay if you are looking for a peaceful, off-the grid house with outdoor kitchen, shower and bathroom between Hilo and Volcano. I stayed there with my 14-year old for 9 nights and we had a really good time. Neil is an awesome host. He picked us up at Kona airport and dropped us off at the end of our stay. He made sure we had everything we needed and more: clean towels, replaced several times, sparkling water in the fridge, fresh coconuts and pineapples from his farm. He loaned us a very nice mountain bike (29", 1x9) for the entire time.
The place is about 15 minutes from the main volcano road about half-way between Hilo and Volcano, so you can easily get to the park or to the ocean. When we stayed there the temperature was always between 64 and 74F. The house is set-back about 100 ft behind a gate, very safe and surrounded by trees. The solar system fully support a fridge, a TV, fast WiFi. The stove is 2-burner propane and there is running water for warm shower, toilet, sink. It's a great place to unwind, relax as well as a good location to explore the region.