Hilo Hawaiian Hotel
Hilo is on the north side of the Big Island, and therefore catches much of the wet weather. They are geared more for business travelers here than tourists, but it is closer to the volcano than the Kona Coast is, if that is your interest. It was ours.
After a long plane ride, made longer by the fact that airlines do not have handicapped accessible toilets, we were glad to find the hotel not far from the airport. The room looked out onto the bay, through some coconut trees. The pool wasn't heated, but the kids enjoyed it anyway. The restaurant was quite nice and I was particularly partial to the breakfast buffet.
The room was a bit smallish, and there was a hump to negotiate in getting out onto the patio. The bathroom would accommodate a wheelchair, but many people with disabilities would have a hard time getting in and out of the tub.
For entertainment, you may want to stop by Uncle Billy's just down the road, and you may want to arrange in advance for a helicopter tour of the volcano and lava flows. It is probably the only way you have a chance of seeing the molten stuff.