I was also told you have to wear a mask hat all times you are outside, even sitting at the beach. The only time you can take it off is if you are in the water, or exercising. If you are just walking on the boardwalk and such, you have to wear a mask, even if there are not any people around. They do check at least some of the beaches and issue citations. This information was about Ka'anapali, on Maui.
I was planning a trip in December, but I may decide not to go under these requirements. I don't mind wearing a mask around the common areas, but I'm not sure I want to lay out on the sand, away from everyone, with a mask on. Same for sitting on the lounges around the pool, though I almost never use the pool.
Correction:
At the Westin resorts, they told me that the whole group had to quarantine until the result was received. At the airport, if the driver is OK, he can still pick up a rental car. If they stop for supplies, the quarantine person has to stay in the car, but apparently they can stop.