Our reply is, well what do you want to do? The island is big, hence it's name.
You're looking at a 2.5-3 hr drive one way if you want to visit other sites on the island.
From our limited experience, we've found that visitors break up their accommodations around their planned activities and events. We'll suggest the following places based off the points of interest around the island. There's no place to stay in the middle of the island because it's a giant volcano wasteland (We think there's cabin's there but they're not worth the stay).
Kona Seaside Hotel
VRBO (Beware of huge "cleaning fees" made known only on check out)
Most other hotels average about $200-$600/ night
VRBO (Waimea will by far be the cheapest- but it's super nice there, just not by the beaches)
Hapuna Beach Cabins (Basically Glamping by the beach)