When I replaced my W124 serpentine belt, I removed the fan shroud first, (and you can carefully get it completely out of the engine bay without removing other parts).
I then loosened and removed the 3 7mm hex bolts from the fan and removed the fan blade out of the engine bay.
This allowed enough room to gain access to the belt.
The belt tension is such that you can easily pry a screwdriver between one of the pulleys and the belt and coax the belt completely off.
Did the reverse of the above procedures to install. Total replacement time: 30 minutes.
Total replacement time on the VW: 1 minute!