You can park right at the trailhead with a California Adventure Pass, but spots are limited. Alternatively, park at the Big Bear Discovery Center and walk a half-mile paved path that links with the trailhead. The climb is fairly gradual for the first mile and steepens in the second. There is ample shade beneath abundant ponderosa pines, but much of the trail faces south, so it gets hot on warm days. Expect cobbly surface and rock stairs in some places. Views get better and better as you climb, and the trail periodically crosses clearings with excellent vantage over the lake.

Cougar Crest Trail technically ends at a junction with the Pacific Crest Trail (PCT), but you can continue to Bertha Peak by turning right on the PCT. On top awaits the widest panorama yet. You can see not only the lake but more of the San Bernardino Mountains, and beyond. On a clear day, you can see all the way to San Gorgonio in the south and the San Gabriel Mountains in the west. A signal station shares the summit, but you can walk around it for views in all directions.

Sources: https://www.fs.usda.gov/recarea/sbnf/recarea/?recid=26375 https://bigbearlakefrontcabins.com/blog/cougar-crest-trail