Given the restricted time frame and location of the itinerary, a feasible yet cost-effective mode to navigate the area is by car or bicycle. Please check any local bike rental stops, but if car hired via the app-based ride-sharing services or rental options would make it easier. A budget of $20-50 is sufficient plus possible added costs for parking fees, tolls, and fuel, that will depend on your preference.
If you have more time, you might want to include visits to Kern River Preserve for bird-watching or the California Science Center for science enthusiasts. Given limited time, you can adjust the itinerary by visiting only one or two of the suggested locations you are most interested in or by shifting the timing slots based on personal preferences.
The nearest airport is Los Angeles International Airport (LAX), approximately 20 miles northwest of Bellflower. Long Beach Airport (LGB) is the closest one at only 7 miles southwest of Bellflower. The latter is a smaller airport, highly recommended for travelers due to its ease of use and less potential crowding.