We enjoyed out off grid stay at Coco Wasi. The Bamboo house was large and the porch as so nice. Rustic luxury. There were some leaks in the overhang so the porch was not fully dry in the rain, but indoors was clean, fresh, and dry. Be ready for geckos and some bugs, although they will likely avoid you as much as possible.
We should have stayed on the property more and used it to relax - rather we went off and explored the area - Hilo (farmer's market, Pho 99, shops), Hawaiian Tropical Bioreserve & Garden, waterfalls, more. All that was great, but we could have used more time art Coco Wasi to recharge and relax.
Definitely ask before arriving if yoga or massage is available. There isn't always a set schedule. Would be an amazing place for yoga! Use the space, they are all so open and welcoming and warm, they will take care of you.