Overall, this was a very good trip. The itinerary is top-notch along well-marked trails, through a variety of landscapes - farmland, ski towns, narrow gorges, along a lake. I recommend the route with the rest day in Zell am See - we had a great day there!
We did have a few concerns with the local tour company. The quality of the bikes rented from the bike shop was not great - my bike was too small for my body but they had run out of bikes, so I was stuck with it for the week. Some of our group had arranged for bikes to be delivered to the starting hotel. It's a good thing others went to pick up in person, because the bike shop had no record of delivery and half our group would have been stuck without bikes for 2 days.
As others have mentioned, the guidebook is hard to follow. However, the general routes are along bike trails that are well marked. We did pretty well by following the path signs to our destination each day.
Our biggest mishaps were with the hotel and luggage transfer. We were a group of 4. About half the time, we had two adjacent rooms in the same hotel - no problem. Other nights, we were split across two different hotels. One night, we had a really strange configuration - 3 of us had a triple in one hotel, while 1 person was assigned to a different hotel across town. Every time we got split up, some luggage went to the wrong hotel. It didn't help that the tour company only provided 1 luggage tag per room. Seems like an easy fix to include an adequate number of luggage tags per traveler. Our final night in Salzburg, our hotel had no record of our reservation. It took awhile to figure out the issue - our reservations had been made against the wrong name.
On the whole, this is a lovely trip. Unbeatable scenery and value for the price.