Re the Hilo side, there's a bit of a mini-review (along with some other topics) here of the
Dolphin Bay Hotel in Hilo
A couple of weeks ago I spent a couple of nights at the Hilo Seaside.
A local-owned and run hotel. Decor funky and charming, straight from the '60's. Had a nice room (if small) overlooking the koi pond (who had trained the lanai lurkers well in throwing food to them). Met a few "characters" there. Rooms were very clean, if older. On the weekend, the location can be noisy, though.