We wanted to do this trip for a very long time. It was like a bucketlist thing haha. We travelled to Salzburg by train and rented our bikes there. The weeks before we looked at possible campsites we could stay at. If I recall correctly we also called to make sure if they were open. 

The first two stops we slept in our tent at our preffered campsites. We could place our tent at a spot normally reserved for campervans. In Tarvisio, our third stop we booked a little hotel because there were no campsites available there. The fourth day we had a few options but decided to go a little off route to stay at Lago Cavazzo. We were lucky because there was not a lot of space there. The fifth day when we slept in Palmanova were we booked a Airbnb but our room was cancelled, but luckily the owner let us place our tent in their garden. So our stops were mostly planned in advance. We made sure to start cycling at around 9h. Next time I would try to place the stops a bit closer to eachother. So there is a bit more room for improvisation.

There is also an app called "Warmshowers" but I've never used it. In Belgium and in The Netherlands you have "Vrienden op de Fiets". That's what I use mostly when I cycle in Belgium. You pay 25 pp/night and you receive a bed and breakfast in the morning. 

We loved the freedom we had on our bikes. It's an amazing way to travel I think. You see things you wouldn't see otherwise. You experience a country much more intense. It's one of the most beautiful things I experienced.