This website has information on where an Adventure Pass is required, and where you can buy one.
https://www.fs.usda.gov/detailfull/r5/passes-permits/recreation/?cid=stelprdb5208699&width=full
I acquired the Senior Pass years ago. It is free, and does not have to be renewed. There are a few benefits to age. Can't remember the required age.
I hiked the Spitler Peak Trail on Saturday. Met two women at the PCT junction who had set up a car shuttle and were hiking from the Fobes trailhead to Humber Park. I asked them how the Fobes road was, and they said it was fine.
Had not been on the Desert Divide since the 1970's, and not much then. One or two hikes up around Antsell Rock. No PCT then, only the Sam Fink Trail, which I remember as being little more than bright metal tags hanging from trees, spaced so you could always see the next one.
The Spitler Peak Trail is an excellent trail, though it still beat me up coming down, as I have done little hiking over the last year. Fitness center exercises don't seem to do much for downhill hiking, particularly when you have a wobbly knee. I did a little research on the web, and now know the difference between 'concentric' and 'eccentric' exercise. But everything in a fitness center seems to be 'concentric'.
Beautiful wildflowers. Trail steeper towards the end, with a stream crossing above a waterfall and two trees across the trail. I do worry about the future of narrow trails on steep dirt slopes, since even a few yards of erosion can make a trail problematic.