Thanks to LA Trail Hikers, I have a new reference that I feel truly rates the hikes correctly. They also offer free trail guides each week so if you're in the area, check out there site for upcoming hikes.

I will use their guide to trail levels when rating the hikes that I go on. The following information is literally taken verbatim from their site so if you have any questions, please contact the LA Trail Hikers contact person for more information.

Hike Levels

The following are a general guideline of hiking levels to express the difficulty level (1 the easiest, 10 the hardest) and recommendations for our hikes.  These strenuous levels are based on a combination of distance, altitude gain, rock scrambling/stream crossings (if any), animal/young hiker safety, terrain type, and the overall difficulty of the trail as previously experienced by our hike leads. Please note that each hike is different and may require a few extra notes as expressed by the designated hike lead.


HIKING LEVELS
Level 1:  Beginner – The easiest type of hike you can get with no real inclines. Stroll in the park.
First Timers, Beginners, Most Kids, Most Teens, Dogs, Water Required

Level 2:  Beginner – Next level with some simple inclines.
First Timers, Beginners, Most Kids, Most Teens, Dogs, Water Required

Level 3:  Beginner – Hikes with some basic experience, experience gain.
First Timers, Beginners, Some Kids, Most Teens, Dogs, Water Required

Level 4:  Moderate – Good inclines with some stress on further distance.
No Beginners, No Kids, Most Teens, Dogs, Water Required

Level 5:  Moderate – Inclines start to get more intense. Gain and distance goes up.
No Beginners, No Kids, Some Teens, Dogs, Hiking Footwear Recommended, Water Required

Level 6:  Moderate – Simple switchbacks and distance increase. Endurance and Stamina required.
No Beginners, Adults Only, Some Dogs, Hiking Equipment Required, Hiking Footwear Recommended, Water Required

Level 7:  Moderate – Expect some long inclines or switchbacks. Gain and distance increases. Long hours.
No Beginners, Adults Only, Experienced Hikers Only, No Dogs, Hiking Equipment/Footwear Required, Water Required

Level 8:  Advanced – Intro to Advanced here. Distance hikes and more than moderate experience required. May Last all day.
No Beginners, Adults Only, Experienced Hikers Only, No Dogs, Advanced Hiking Equipment/Footwear Required, Water Required

Level 9:  Advanced – Long distance hikes which may take more than 6 hours with great gain. May last all day.
No Beginners, Adults Only, Experienced Hikers Only, No Dogs, Advanced Hiking Equipment/Footwear Required, Water Required

Level 10:  Advanced – Longest hikes and/or greatest gain/inclines through out the hike. May last all day.
No Beginners, Adults Only, Experienced Hikers Only, No Dogs, Advanced Hiking Equipment/Footwear Required, Water Required