I can only speak personally as a retired senior who has remained relatively isolated for the last 4 months. I also don't expect that to change significantly between now and December, or even longer, especially since no vaccine is expected to be widely available by then.
We look at the re-explosion in cases in the USA and the inconsistent use or enforcement of masks, hand washing and physical distancing. If that doesn't change, at least in the areas we would be visiting or travelling through, then we will feel very uncomfortable coming south this fall or winter. Our next trip is to HGVC Plantation Beach Club on Hutchinson Island in Florida in December. The potential danger is not in being there so much, as in the getting there. Once there we can stay somewhat isolated, just as we are when at home.
While we can at least avoid the additional issues of flying, we still must drive down the I79/I77/I95 corridor to get there. Every time we have to stop to use a public washroom, get food, or stay somewhere overnight, is a new potential risk. This is particularly so if locals are not staying safe themselves or following proper medical guidelines.
It is up to each state and community to make the decisions that it feels are best for it, but then we have to make the final decision on what is right for us. At the moment I would assign at most a 10% probability that we will keep the booking. Let's hope that changes, but I am not optimistic. I suspect even our January trip to St. Martin is not likely. If so, it will be our first time in decades without any travelling for over a year, but safety comes first.