Nice ride, Erik!
I'm setting PRs since I started training for (and have since ridden in) the race, too. Bonus is on trails I've ridden hundreds of times! It's a nice feeling to know that it's possible to improve even with age. There are definitely days where my knees are really stiff, and I can tell I've got something going on with what feels like the MCL on the left knee, most likely a remnant from the crash that fractured my right tibial plateau, but I just keep at it. No swelling, just stiffness and mild pain that is intermittent.
It's hot and the air quality in the evenings is getting really bad, so I am very grateful to be able to ride in the mornings right now.
I will say that riding longer distances seems to be a really good way to improve speed overall, or at least to throw in about 2 longer (say, 13 miles or so) rides per week. My speed on the ride today averaged 7.4 mph, up from 6.7 mph just a few weeks ago.
Oh, and I put the 30 tooth chain ring on and rode with it this morning. I like it! It definitely gave me a little bit more power, dare I say, on the one steep pitch I climbed today. It's a gravel/dirt road that is washed out and just a mess, and it's quite long and gets steeper and more washed out the higher you go. I was able to stay out of granny on it and still felt like I had some oomph in my legs. Previously, I'd run out of gas even in granny. I'd still make the entire climb, but I was pushing max effort. Today felt a lot better.