I guess Passport Canada has really amalgamated as there are only 2 locations in Mississauga to get this done? I was surprised too when I Googled it. The other alternative on Glen Erin has paid parking, so I opted to go to this Central Parkway "Mall" instead. ;)
(It's not really a mall, btw, but more of a neighbourhood plaza in the Valley.)
This Passport Office is newly renovated and is no longer upstairs in some dingy digs, but on the main level. It's pretty centrally located, so you can't really park "too far" from it. As soon as you step into the mall, there are clear signs pointing you in the right direction!
If you've filled out all the forms in properly, the process is pretty smooth. You stand in one line for someone to quickly scan your app and give you a number. Then you have a seat where you wait for your number to appear on the digital boards located throughout the room.
I went this afternoon and from the time I got my number - when I was served was approx. 20mins. Not too bad.
Note: There is no free WiFi.