My SIL moved to the Big Island two years ago. They initially bought a 2b2ba condo and rented it out. One year later, she moved there and got herself a full time job so she wouldn't get bored. She is only 58. She seems very happy.
We stayed at a VRBO in Portrero Hill. We loved it!! We had a car, and it was not bad driving around. Check out the groupons. We found some activities that were worthwhile to see.