I take my 7 year old up to ride fairly regularly. After some experimentation, I feel like the blue lines may actually be easier than Evergreen. That being said, the xc loop is by far the easiest descent to handle for a raw beginner as the grade is relatively moderate top to bottom. From there, I've introduced him to playground, as it's the shortest climb, and there are good sight lines when things start to get steeper. I haven't taken him on Evergreen in a while, but the issue we had when we first approached it is that there are some relatively steep and tight switchbacks that got into his head.
Beyond that, if I was up there with an teen/adult who was familiar or comfortable on a bike, that they should be fine on anything other than jumpline or comet. I'd just be sure to follow the signs for "easier route" on Arrow.