Are you starting class or jumpseating? Only reason I ask is because of length of stay as there are a couple of options:

1. Do an off airport parking deal and have them take you to the fedex terminal - tell them your an employee, should be $10 per day.
2. Take a bus to any terminal and then take courtesy bus 66 - water shuttle. That will take you to the terminal.
3. Hotels may work for a night or so, but I wouldn't push it past that.

Also, if you live closer, MHT is a good option as it doesn't cost anything to park there.