Gravel bike for Lutsen 99er?

Anyone ridden the Lutsen 99er? Would it be doable on a gravel bike? My plans for a MTB fell thru this year so I’m kinda stuck with what I have. The mix of pavement, single track, and fire roads seems to suggest it’s possible. Appreciate any insights!

Yes, absolutely. My good friend is doing it again this year on his single speed drop bar bike with 40c tires.

Doable? Yes. Ideal? Probably not. Great for some sections but you will get beat up on the rougher terrain.

I know someone who did it with a gravel bike but with a suspension fork and he said it was a long day.