Hello Taffy
We have done this route many times and with different outfits. The Fern Pass has lots of bends and can be slow and very busy especially on Fridays and Saturdays but it is not a difficult pass. This is a very picturesque route but is is not a fast one. I now prefer to turn EAST at Innsbruck and cross into Germany near Rosenheim. The motorway around Munich is quick and easy and then you rejoin the other route neat Ulm. Also there are several good camps just off the Motorway at junction 73 near Augsburg. Being a motorway route there are no long or steep climbs and we have not encountered any major hold ups (so far). If you are worried about any passes then this route is very easy.
Hope this is of use to you.
Happy travels BarryB