Let's see...
Forest? check! Starting line at 8470 feet up Mt Charleston, just shy of the ski resort.
Challenge? check! The trail led straight uphill for over 3 miles, then it really got interesting. The trail got skinny and rocky and went uphill and down all the way to the 4 mile turn around. We topped out at 9400 feet, but the downhill made up for it. I crossed the line, arms flapping to either take off flying or just keep my balance at 8:45 min/mile pace on rubbery oxygen-deprived legs.
It was beautiful up there, not so cold, and the aspen are turning color. I'd recommend a trip up the hill, it's a nice reminder of what "seasons" are. Ours tend to run hot and windy to just plain hot.