Traveling in Glendale is convenient, you can rent a car, use public transportation like buses or rideshare services like Uber or Lyft. Taking the Metro is also an option to explore nearby cities. Expect to spend around $5 - $50 on transportation per day.
If you have more time, you can visit the nearby cities of Pasadena and Burbank for more sightseeing experiences. If you have fewer days, you could eliminate Universal Studios, Autry Museum of the American West, or Griffith Park. Alternatively, swap out some activities for leisurely walks or trips to nearby cafes and restaurants.