FS2004 KBFI GA

Boeing Field (KBFI) is close to the Seattle (KSEA) International airport, which is the default airport for FS2004. 
The airport has one long 10000ft runway 14R/32L and paraller short 3709ft runway 14L/32R. There is a General aviation area east of the short runway  - see the pictures.  This download shows the GA aircraft in this area "KBF2" forced to use the short runway only. The same tower frequency is used for both KBFI and KBF2, which basically is the same Boeing Field airport.

The FS2004 default aircraft are used at KBF2, so there is no need for any add-on aircraft uploads. The GA aircraft either circle Boeing Field airport or fly round-trip to adjacent airports, eventually landing back on Boeing Field's short runway. The KBFI main traffic is not affected but tower might warn you if you have another aircraft landing or taking off in the same runway direction. 

****Selecting KBF2 for landing (with aircraft capable to land on 3709ft runway!). ATC will vector you towards the Boeing Field airport and switch you to Boeing Field tower 120.6 for landing onto the short runway.
****Selecting KBFI for landing, ATC will vector you towards the Boeing Field airport and switch you to Boeing Field tower 120.6 for landing onto long runway with ILS. But there is still an option to select the short runway.