The best option for getting around the city is by car. You can rent a car at the Los Angeles International Airport, which is about 36 miles from Rosemead. Ride-hailing services are also available, but depending on your itinerary, they may become expensive. Expect traffic, and allow plenty of time when planning your transportation.
If you have extra time, visit the El Monte Historical Museum or experience the adrenaline of indoor skydiving at the iFLY Indoor Skydiving. If you have less time, you can skip some of the museums or parks and spend more time exploring the San Gabriel Valley Wineries or having fun at the Legg Lake Recreation Area.