Question : Have you considered flying out of an airport besides Tijuana Airport (TIJ)?
Answer : Departing from Tijuana Airport is not the only way to get to Beijing Capital International Airport. Try searching for flights from San Diego International Airport (SAN) as well. Over the upcoming months, flights from SAN to PEK are being booked 18% cheaper than flights from TIJ to PEK. Being only 18 miles away, it's easily accessible for most.
Question : How many days should you spend in Beijing?
Answer : The average time spent in Beijing by travelers from Tijuana is about two weeks.