So will they accept if you say you sleep on trains, no hotel?

For 3 months, it’s okay.

If there a quarantine applies they won´t accept you sleep on trains and in case of Netherlands Germany said there will be no transit exceptions :)
All control Italy,Germany,Switzerland,Belgium
Austria is just a example where i had my own experience earlier this year with quarantine :)
As i said just adap your Route (according the restrictions) and stay away from Risk Countries (this change worstcase daily)

You can travel as you want but we all just wanted to warn you about the quite high fines that can be charged if you break the restrictions :/

For entering Italy you have to proof where you have been the last 14days if not in your Citizenship country.

That sounds like too much trouble. But if I cross the borders by hitchhiking, I should be able to remain unnoticed. Or?

It´s up to you if you wanna try it or not They can control everywhere at the border and in a sector 30kilometers arround without any reason

I don't t think they can control when you are not crossing a border.

Thanks for all the warnings though.

Hi, 
It sounds like you are determined to travel whatever anybody says. A friend tried the same and thought he could sweettalk the Spanish border guards. He is now in quarantine at his expense (1,500 euros) in a local hotel - NO home quarantine allowed. They marched him to a cash point where he could only take out 600 euros and then drove to a hotel where he had to do a bank transfer for the other 900 before they left. They took his passport and explained to the hotel staff to place it in the hotel safe and NOT return it to Tony or they could be fined up to 20,000 euros. They call him at least once a day and always on his hotel room phone. One day he was in the shower and did not hear/see the call. Within 30 minutes two officers were at his door.   

Those are the risks.