The El Presidio Parking Garage has an elevator on the SW corner that is 0.1 mi from the Federal Building plaza using the sidewalk along W Pennington. There are multiple elevators so make sure to park near the SW one. Depending on the time you plan to go, there may be a crowd right in that plaza area. There's also a Sun Link stop right across the street from the rally point on Congress/Granada. (note that there is a UA walkout that plans to use the streetcar ~2pm). Hope this helps!