When the Governor shows up, the Old man states that he doesn't even own the house he lives in. Than McGarrett says he has good news, the appraiser low balled you and they will give you $60k and a moving company will move your home". The old man is happy with it never mentioning he doesn't own the house.
When Amy Nichols (Elsie Russell) breaks through a police barricade in an old car to bring some soup to hostage-taker Clinton Palmer (Barnard Hughes), it is clear even without freezing the video that a male stunt driver and not the elderly Ms. Russell is driving the car during most of the shots before the vehicle is stopped in front of the hotel.
The car McGarrett left the office in to the situation at the hotel was the Mercury Marquis. In route it was a Park Lane, then again at the hotel it was the Marquis.