Always hard to judge how strenuous a hike is from reading reviews cause you don't know people's fitness levels. This will definitely present a challenge for people that don't exercise much as the first part is fairly steep and continues for probably about 30-45 minutes. We took the trail up to Tom's Thumb and back which took at least 2 hours round trip. We started early like some recommended to take advantage of shade on the first part of the trail at that time of day and it was a great idea.
The trail itself though is very nice aesthetically with great views and an interesting path. The trail to Tom's Thumb is pretty well marked. The view from Tom's Thumb is great and you marvel at seeing the trailhead parking lot off in the distance, seeing where you started from.