Overall, a very nice ride. I parked at Isherwood Way, near Paseo Padre Pkwy. Once I parked, I noticed there are two trails along the creek. The inner trail is gravel and dirt. The outer trail is paved. I took the paved trail towards Niles Canyon. Very nice ride and pretty views. It was about 6 miles there and back to the parking lot, so I went the opposite way. Going that way was not as scenic, and had more people, but still a decent ride. Throughout the ride, I noticed several patch up work on the paved trail, so the ride wasn't very smooth. Flat ride, with the exceptions of going under the bridges, in which case you have a minor hill.
Will probably go again soon. It is good training trail for an upcoming race.
This isn't 5 miles. It's at least 6. My GSP tracker said 6.5.
And I would not call this easy for beginners. The first and last 1.5 miles or so are flat, but that middle few miles is pretty steep for newbs. 1-5 I'd give the whole thing a 3. 1 being totally flat. 2 being slight elevation gain. Nice views. Cool if you don't feel up to hiking Mission Peak.