Beautiful scenery, safe cycling The vast majority of this trip is in cycle paths separated from road traffic with some lightly trafficked roads and only very occasional roads with significant traffic, and even then you are usually separated from them by a barrier of some type: in fact, if none of the above applies, you're probably 'lost' although that, too, is really difficult to do as the river is hard to lose and the signage is excellent! A large proportion is on a Euro cycle path from the Black Sea to the Atlantic and it is very well maintained: UK councils could learn a thing or two about maintaining safe cycling environments from the Austrians. The scenery is at times spectacular and varies from day to day as the river meanders across Austria. The accommodation we got was generally very good and there was usually somewhere good to have dinner in the evening. Lunch stops were a bit thin on the ground but we usually found somewhere. The bicycles were heavy but in very good nick: the route is mostly flat and any slight downhills outnumber the uphills - which often related to gaining the altitude required to cross over the bridges over the river rather than anything else. There are churches in abundance, from big to small and most towns have a schloss (castle). There are some spectacular monasteries and when you get to Vienna, it is clear that it was the centre of the world for quite a long time with monuments and buildings to show for it! The distances are manageable - on the last day, you can get a train to cut the distance down to about 50 km but we decided to cycle from Krems to Vienna (about 90 km) and we survived!
The trip was overall very satisfying although the full day in Bad Ischl at the start (meaning 2 nights there) as well as a night at the end was too much in the one place.
The Dolomites were indescribable, you could do a photo shoot every 5 mins. Routes between towns were all on bike tracks and well chosen. Hotels were comfortable of relatively east to find.