Mackenzie was so weak. The lava flow stuff was OK mostly flat and endless. Would like to try the Bunchgrass trail from Waldo lake to Oakridge. 40km
I though the first 10mi were a nice, scenic slightly techy XC cruise. The swimming in Tamolitch Blue Pool is definitely exhilarating. The last 15mi gets progressively more dull. The group I was with found ourselves unconsciously riding faster and faster despite fatigue just to get it over with.
A trail that's likely much better in the same area is the Olallie-O'Leary-Castle Rock-King-Castle route. Unfortunately I haven't ridden the whole thing. Day 2 of my trip was wasted in Bend so on day 3, I only had time to ride ~5mi up and down King-Castle before heading home.
Here's a helmet cam vid (not mine) that gives a fairly good overview. EDIT - fixed the embed, but you have to skip ahead to 8:34 to get to the typical part of the descent.
https://www.youtube.com/watch?v=WqxIIn0FnSk
The climb to get up to the ridge that eventually feeds you into that descent is supposed to be pretty grueling though.
My dislike of Bend is probably because I feel like it cheated me out of a chance to ride that whole route. Mind you, if I hadn't spent the day in the Bend dust bowl, maybe the forest wouldn't have seemed so vibrant.