This is a fairly popular trailhead right off I-70 at exit 218. The hike is fairly short, only about 2.5 to 3 miles, and not real steep except for the first part. Herman Lake is situated at the foot of Pettingell Peak, which is over 13,500 feet tall.
The hike starts from the parking lot and quickly comes up to a junction with the Watrous Gulch trail. Take the Herman Gulch trail to the right. After a short distance, the trail steepens and you begin climbing to get into Herman Gulch. After the first half mile or so, the sounds of I-70 can no longer be heard as you near the creek flowing from the lake. The trail levels out after the first mile and you begin walking up Herman Gulch's scenic valley. Flowers are abundant and the scenery is great.
Finally you get to treeline and you resume climbing only a short distance to a small pond near the lake. Just a short distance past the pond, the trail ends on the east side of Herman Lake. The lake is quite scenic, situated just above treeline. It can get quite cold here, as the winds blow right off the divide. 
We fished for about 30-45 minutes and no one even had a bite. We did see some fish in the lake, but I think that saying they were one inch long would be too much. They topped out at about half an inch.
I would recommend the hike to anyone wanting a fairly scenic trip with some great flowers. If you are a fisherman, don't bother!