The route for Boreas Mountain from Boreas Pass is simple and straightforward. From the parking area, head east past the structures and chart a course uphill toward Pt. 12,815. The terrain north of the point will be the easier, but there are many ways to "skin this cat." From the parking area there will be an initial uphill through generally open, grassy slopes to a bench-like area. Then the angle of ascent will begin to increase and you'll have to deal with some willows. At least they are not the man-eating type and a little careful route finding will avoid getting tangled in the willows too badly.
Soon the willows begin to play out as you continue up on a mostly grassy slope. Once you intercept the main ridge, north of the summit, conditions change dramatically. For a brief while, you'll be walking on sparse tundra with chiprock. But as you proceed south toward the summit, you will eventually arrive at a nearly flat plateau area covered in what we call "dinner-plate" talus. There's a well-used trail through all of this that will take you all the way to the summit where you will find a larger rock shelter to break the westerly winds. The highest point of the summit actually lies a few yards farther south.
We deliberately saved Boreas Mountain to be our final 13er summit and were accompanied by a group of over 20, including family members, friends and some notable Colorado peakbaggers. Our thanks to all who shared with us on that notable day.
To descend, simply retrace your route back down, or follow the ridge back north to the Boreas-Bald saddle, and then continue on to Bald Mountain, also an easy Class 2 hike.
Links to other information, routes & trip reports for this peak that may be helpful.