Is the Allegheny Intermediate Unit (AIU) accessible by public transit?

Yes. You can map your trip to the AIU by entering your starting location and the AIU address (475 East Waterfront Drive Homestead, PA 15120) into the Pittsburgh Regional Transit Trip Planner: https://truetime.portauthority.org/map?selector=tripplanner

Where will this workshop take place inside the Allegheny Intermediate Unit (AIU)?

This workshop will take place inside transformED, which is on the ground floor level of the AIU. Enter through the main/front entrance and walk straight ahead. The lunchroom will be in front of you. When standing in front of the lunchroom, turn right. transformED is at the very end of this hallway.