At this point, it probably makes sense to wait for the vaccine and travel rules adjusting to account for that.
My guess is that most in their 60s and 50s who really want to get it will be able to before early summer (and hopefully also us slightly younger folks) - the raw numbers might seem to make that less than certain, but vaccine hesitancy is unfortunately a thing, so those who want it may find ourselves in a shorter line than overall population numbers would predict. At some point after the age thresholds go away entirely there's going to be a shift and the issue will no longer be about people clamoring to get the vaccine before its their turn, but about trying to persuade the haven't gotten around to its and then the true holdouts to roll up their sleeves.
Plenty of nice riding weather in early fall, too - not the 14 hour days of peak summer, but also not the extremes of heat and sun, either.