Core Skills for all Pilots
Power Grid Management 5: To maximize the power core.
CPU Management 5: To maximize the CPU.
Capacitor Management 5: To maximize the capacitor capacity.
Capacitor Systems Operation 5: To maximize it's recharge rate.
Energy Grid Upgrades 5: Reduces CPU req. for power modules.
Mechanic 5: To maximize hull strength.
Shield Management 5: To maximize shield capacity.
Shield Operation 5: To maximize it's recharge rate.
Hull Upgrade 5: To maximize armor strength.

-Smallest to Largest Site
Burrow > Hideaway > Refuge > Rally Point > Den > Yard > Port > Hub > Haven > Sanctum

-Easiest to Hardest Site-
Hidden > Forsaken > Forlorn\\\

Burrow>Refuge>Yard>Port>Haven>Sanctum have only one difficulty!