Have you done that kind of travel before, in that kind of environment? Where accommodation will be limited, and you are likely to spend quite a large share of your evening going from hotel to hotel looking for an available room, quite likely to be forced to travel out of town and away from the nice things you wanted to see? Forced to do your sightseeing in the middle of the day without much of an opportunity to leave your helmets and riding gear in the hotel while you walk about in shorts and tshirts?

Plus of course the heat, and the fact that a lot of Italy does completely shut down for Ferragosto - the shitty tourist places will still be open, but the self-respecting restaurateurs will be away.

You can't rely on AirBNBs with last-minute bookings - the hosts are likely to have other plans than checking you in at dinner time with no prior warning.

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As someone who has travelled in Italy in August (ugh), and who has just done the Italy-Croatia-Austria-Milan trip on a motorcycle, my recommendation would be to plan out your overnight stops and prebook them. Be conservative with the amount of kilometers you schedule for each day, and for the places where you want to slow down and look around - big attractive cities like Florence, Dubrovnik, etc. - make sure you take two nights' accommodation at least, and have a full day off the bike.

The romance of never knowing where each day will end is very nice when you are traveling e.g. in a campervan, or going across somewhere like Norway where you can pitch a tent two corners off any road and have a reasonable chance of privacy and a great view. But you will be on a bike, in a densely populated area during high tourist season. You will be MUCH happier having a pre-researched pleasant destination to aim for, and if you get there a bit earlier in the day, that's all the better! And it definitely does NOT preclude you from detours, changing the path that you take to your destination at the last minute, because you see there are roadworks or you're too tired for switchbacks.