[Cyclopath]

Haven't done much MTBing, I've rented one a couple times. Did 2K ele on Sun Mountain this spring, and 3K to get to the top of Miller Peak. Otherwise it's all road bike, with a bunch of 2K to 2.5K days, about 300 to 400 miles a month. I got a power meter recently, I'm surprised how useful it's been for pacing myself. Sounds like I should probably go for it. Also: really light wind shirt, or a slightly heavier wind breaker?

[Riverside Laker]

Warm days are best. The day I went was chilly. My fingers got really cold. Wore a wind breaker jacket.

[joker]

The "ah, duh" answer on the clothing question is "it depends on the weather." But yeah, it can be cold. The first time I did it was a sort of showery day and we got a bit hammered by a squall on the way down - was really nice to have a long sleeve wool shirt and a decent rain shell to put on for the descent on that day. The second time I did it was a warm day and I don't think I wore anything but my t-shirt on the descent, but I had my rain jacket and I think one other top layer with me. Might have worn the rain jacket as wind protection for the upper part of the descent - I forget. You mention "MTBing" - this is of course a road ride (though the bottom 1K is somewhat rough pavement, but it was fine with my relatively narrow tires; my wife was only slightly annoyed in that part while on her pingy aluminum road frame). I used my road bike, which doesn't have particularly epic hill gearing. Might have been one or two pitches where I stood up, mostly for a change of position for a short bit. If you've been doing some 2-K rides and have gotten in some 3+ hour rides I am guessing you'd enjoy the ride as long as you like relentless climbs.