The Lower Sam Merrill trail is a steady climb with many tight switchbacks. It's best to climb this in the morning as the trail is West facing and there are very few trees for shade. At the top of the Lower Sam Merrill trail, you are rewarded by great views and some local history from the ruins of the old Echo Mountain Resort and Mt. Lowe Railway. Get out really early to avoid heavy hiker traffic on the weekend or break out the lights and ride it at night.
LSM is one of the most popular hiking trails in the Los Angeles area. Expect to encounter plenty of hikers any day of the week. Yield the right of way and be friendly here as many on the trail will be nervous about the steep trail and tight quarters. It is recommended to climb LSM and descend via other trails like Sunset Ridge Trail.