North on I-25:

Take Alameda Exit (Exit 207B)
Turn Left on Alameda
Turn Left on S. Platte River Drive
Proceed to 455 S. Platte River Drive

South on I-25:

Take Alameda Exit (Exit 208)
Turn Right onto Alameda
Make immediate Left onto 
  S. Platte River Drive
Proceed to 455 S. Platte River Drive