Dear Shirine Lim,
The fast way to transfer from Shanghai Pudong Airport to Hongqiao Airport would be taking a taxi. If your flight arrives at 4:30am, after you claim your luggage, it will be at 5:00 am then. If you hop on a taxi at that time, as it is in the early morning without traffic jam, it will take about 45 minutes to arrive at Pudong airport. That mean, you may get o Pudong at 5:45 am. It is enough to check in flight of 7:20am. You can check in through express lines, which would be much faster.
Of course, the two airports is 60 km from each other and there will be additional taxi fees in the early morning, so you will cost about RMB 300 for one way.
If you would like to take public transport like bus or subway or Maglev Railway, it is kind of hard. There is still not Maglev Railway train, and Metro Line 2 does not go into Pudong airport during this time period. You can take taxi from airport to Guanglan Lu Station of Metro Line 2, which will cost about RMB 50. and then transfer to Subway Line 2 from Guanglan Lu Station. It should departs at 5:30 am and arrive at Terminal 2 of Hongqiao Airport at 6:05 am. The advantage is that the subway operates on time with no delay. But as your arrival in Hongqiao is at 6:05, possibly later than the time, you would be not possible to check in the flight. But you all ready check in online and got the boarding pass, and you just need to check luggage, it would be must fasted. By this way, the expense of transfer would be must cheaper.
If you are worrying about the language problem, you cal also rent a car with driver and English-speaking guide to help you for the transfer, this would be much easier for you. But the cost would be much expensive than taking the taxi. TopChinaTravel can offer car rental with English-speaking guide for airport transfer for you, if you need this, you can send us some details regarding to date and pax to
sales@topchinatravel.com. We would send quotes back for your consideration.
You may choose the best way to do the transfer. It is your choice.
Any further request or question, please feel free to contact with us.