There is subway available around 5:30am in Luban Road. You can use Line 4 to Century Av, and then change to Line 2 to Longyang Road. The first maglev train to Pudong Airport leaves Longyang Road station at 6:45am. Make sure you get to Longyang road maglev train a bit early than 6:45 and then catch the first train to Pudong airport. It will be 7am. You have enough time to check-in.

Thanks for the information.
Sorry I forgot to mention that there are six of us, so is this still the best (in term of cost) route, or should we just take the taxi

I think you could take two taxi from the hotel to reach Pudong Airport directly since your flight will leave early in the morning. The fare should be around CNY120/cab, much cheaper and convient than taking metro and Maglev.