I used to do that on weekends for a great workout...and thankfully that ride was all paved. Not sure I would have made it up a "soft" surface. Don't think any sections quite hit a 40 degree grade, but it was fairly steep coming up from PB. I didn't make it on my first attempt, but the more I rode it, the easier it got.

I thought I was in pretty good physical condition, until I moved to San Diego. Those people were on another level of fitness...lol (Clearly I'm talking about the people who take their fitness seriously, not the "Walmart shoppers" of CA.)