We were lucky enough to get a cabin for one night at Waiʻanapanapa State Park, allowing us to spend more time hiking at this end of the island without worrying about driving back to the other side the same day. The black sand beach is lovely, but when we went in February, it was a bit too dangerous to enter the ocean. There are definitely rocks all around, and it's the side of Maui where the waves are larger, so be careful. The high surf did let us see the blowhole in action - great fun to watch the wind carry the sea spray for yards into the park.
Campground: The campsites we saw don't really have vegetation between them, but you're here for the location and the beach, and there aren't any other economical overnight options in the area, so that is neither here not there. Would definitely recommend staying at the park if you'd like to spend more time in this corner of the island.
Cabins: We stayed in a cabin, which are usually two-night minimum, but we planned our trip around a 1-night only availability to get around this rule (~$100/night). Our cabin (#9), didn't have a direct ocean view, but it did sit a bit above the tree line and nevertheless had a great view. It was also intermittently pouring, so a cabin was ideal for our February stay. For tourists, there are some hurdles to booking the cabins (you need to bring your own sheets, towels and soaps, which many folks don't fly to the island with). The cabins have 3 sets of bunks (4 beds total in a bedroom and 2 beds in the living room). We slept in the living room as the mattress condition was better and the mosquito nets on the windows in that room didn't have holes. The cabin has water and electricity, but no AC, so we just slept with the windows open and it was comfortable. No window coverings. To avoid ripping the mattress covers or scratching the floors, there is no moving the mattresses or the beds. There was a bit of a smell (maybe the drain, maybe oxidizing steel sink and hotplate) when we arrived, so I did a thorough clean and blocked the drain with a towel. The cabin will be pretty much the way the last guests left it so I'm sure conditions will vary - our bathroom and floors were clean for cabin conditions. No complaints there. The bathroom has a shower, sink and toilet. the kitchen has a fridge/freezer, microwave, hotplate?, and sink. There is a table and 4 folding chairs inside and a built-in picnic table on the porch, and a grill for each cabin.
That all may not sound luxurious, but we really enjoyed our night here! The porch was large and each porch is designed to face away from other porches and towards the view. It was beautiful watching the sky change at sunset and sunrise. Staying here was much more economical than our other options in Hana. Most importantly, staying over night removed the time stress of doing the road to Hana. We were able to stop, hike, picnic, etc. as often as we wanted on the way out without worrying about a time crunch. We checked out the town of Hana after checking into our cabin and had a relaxed meal across the street from the entrance. We were able to add a 3-hour hike in Haleakala national park (Pipiwei Trail - recommend!) the following day and since that was a hot day, it was nice to start before the sun was too high and the parking lot was too full.