I've done this route a few times -
https://ridewithgps.com/trips/6797681I'd recommend a slightly larger tires than for the DM60 -42c+ would be good. There are some chunky bits.
Apparently the top entrance to Maryhill Loops road is quite emphatically closed, so this is probably a better, more fun option than the tradional DM60.
No idea about specific "event" information -just routing.