Running at Disneyland updated on 6/28/2015 during Disneyland family vacation.

Mickey Mouse
There are two main options for running if staying at one of Disneyland Resort Hotels: through Downtown Disney or around the perimeter of the parks. The two routes can easily be combined,. A map is available at Guest Services in the lobby of the each of the hotels.
The Downtown Disney route is a flat out and back. It is 0.4 miles from the Sorcerer Mickey hat at the Disneyland Hotel to the bag check area at the entering the courtyard between Disneyland and Disney’s California Adventure parks. If you run early, at least 1-2 hours before the parks opening, you can also circle the courtyard, which is 0.2 miles. This makes for a nice 1 mile out and back. The shops and restaurants are lit in the early morning and the area is empty other than the cleaning crew and few other runners and walkers. Most of the shops open at about 10 a.m., the restaurants earlier. The area quickly becomes very busy as the day progresses, and the crowds grow through the day and evening. Starbucks, 0.3 mile from the Sorcerer’s hat, opens at 5 a.m., enticing you with its aroma.
For longer runs and if you want some hills, try the loop around the parks. The Grand Californian and Paradise Pier Hotel are both on Disneyland Boulevard and have direct access to the loop. From the Disneyland Hotel, it is 1/2 mile to reach the loop. Go straight out the front and then take a right on Magic Way until you reach Disneyland Drive and the loop. I am describing running the loop clockwise. The north half of the loop is not as scenic You run on a sidewalk right next to the road in front of motels and strip malls with a fence blocking most views of Disneyland. Before daylight though, as you start down the hill toward Ball Road, you can see the parade floats through the fence in storage. If you run after daybreak, looking to the north and to the west on Ball, you can see the outlines of the mountains in the distance. As you run uphill towards I-5 on Harbour (again after daybreak), look to the right and you will see Matterhorn and the top of It’s a Small World. Be careful though, because the I-5 off ramp is the most risky part of the run. There were several homeless people sleeping on benches each morning along Harbor Blvd. People were waiting at the bus stops. It did not appear to be unsafe, but always be cautious.
The south half of the route is much better. Near the end of Harbour, the Tower of Terror is easily seen. Along Katella Ave.,you pass between rows of tall, stately palm trees while viewing the tops of the cliffs from Radiator Springs, California Scream, and Mickey’s Fun Wheel. On Disneyland Blvd. you continue to pass between rows of trees and landscaping and have good views of the Paradise Pier Hotel, the Grand Californian, and Downtown Disney. The resort loop is approximately 3.0 miles long. Most of the run is flat, but there are three “Florida Hills” with an underpass on Disneyland Drive at Downtown Disney and 2 overpasses along Ball.
To combine the two routes, follow a path off of Disneyland Drive under the monorail between Downtown Disney and Magic Way. There is a sign showing the way. The path ends, conveniently, across from Starbucks. I call this the “feral cat trail” as I encounter the famous felines along this stretch each morning check out Disneyland cats on Istagram).
Cautions: On the resort loop, you have to cross traffic a few times. Stop and pay close attention, especially at the ramps to I-5.
Pollution worsens as the day progresses.
Pay attention to people around and take caution on the resort loop when running alone.
Recommendations: Run early: the air is cleaner, the traffic is less, and there are less people.
Do not wear headphones on the park loop as you really need to be aware of your surroundings.
Use caution running alone along the park loop..
I’m in town for a conference and I like to go running. I ran the perimeter which was fun but I’d love to know if there’s an option for early risers to run inside the park then leave before it opens. I’d get a kick out of it and certainly pay for the opportunity if it were offered.
I would love to run in the parks too, but I have not found the option. If you stay at the Grand Californian Hotel, then they do offer an early morning walk through California Adventure, or did the last time we were there. We are going back to Disneyland in the spring; so I will check it out again.
Sorry for the delay in response. We just got back from a Disney Cruise.