It is highly recommended that you rent a car for this trip to allow for easy transportation around the Bradbury area. All of the locations listed are driving distance from each other, with the farthest location being a 30-minute drive from the starting point. Car rental rates vary, but the average cost for a one-day rental is around $50-$80, depending on the rental company.
If you have more time, consider adding a visit to the Los Angeles County Arboretum and Botanic Garden, located just a 10-minute drive from Monrovia Canyon Park. If you have less time, skip Mount Wilson Observatory and spend more time exploring the gardens at The Huntington Library. Additionally, make sure to pack sunscreen, plenty of water, and snacks for the day.
The closest airport to Bradbury is Ontario International Airport (ONT), located approximately 30 minutes away by car. Other nearby airports include Los Angeles International Airport (LAX) and Hollywood Burbank Airport (BUR), both of which are around an hour's drive from Bradbury.