8500 miles in a season??
JP!!
Obvious you live in a slightly warmer climate than we here in western new york.
Tell you what I've learned.
#1 I am no longer in my 20s or even my 30s and doing 20+mph mile in and mile out and hitting the boston hills south of buffalo or the escarpment north of buffalo at 17mph is going to have someone dialing 911.
#2 I get myself to the very back of the pack.
That allows me to gauge everyones speed and compensate accordingly. As the miles roll by I can stay where I am or begin to move up thru the pack picking the pace I'm comfortable with.
The last 3 miles of the ride become the sprint. Given I haven't wasted these 66 yo legs and lungs by going out fast I often wind up with the lead group as we roll into the lot.
I tend to pick and chose my riding days.
85+degrees and high humidity..uh uh.
I'd be toast.