You can move the aircraft to any airport you want,preferably one with long enough runways and ILS/GS facilities.However,I would at least try to follow a tutorial at least once to familiarize yourself with initializing the aircraft for position (IRS) alignment,and entry of FMS data.Its too bad that KSEA is the default airport for FSX,since it has possibly the worst frame rates,but thats the way it is .Ask more questions or check FAQ's for further help.Its a learning curve for everyone.Good luck
Ron