Camping at Hosmer Grove was real chilly so bring a warm jacket, hat and gloves. The hiking book we use is Hawaii Big Island Trailblazer. It has a nice selection of dayhikes with good directions. We reservedd a cabin in the crater for an overnight stay. Awesome experience, spectacular star gazing. Says George
Halemauu Trail has a total elevation difference of 1,692 feet which is about average. Now, this is roughly a 2.5-day backcountry hike, so make sure you've got all your overnight gear packed. Keep in mind that this is a long backpacking and hiking trail, so don't forget to pack enough supplies. Being 16.6 miles long; it's a long hiking trail. Halemauu Trail is a one trailhead backcountry hiking trail, so you'll be backpacking it in and back out. Halemauu Trail goes through some very different elevations, and that means that some parts of the hiking trail could be very different from other parts of it.