Going to Hawaii from east coast, I recommend going the whole way on the same day. Returning home, if you don't like red-eye flights, you should stop somewhere for at least overnight. My family will be stopping for overnight plus a day, and do some sightseeing in either SF or LA (we'll choose based on price). Depart HNL in the afternoon, arrive in California at night, stay two nights in a hotel, sightsee/etc, then depart the next morning, arriving late in the day on the east coast.