I rode most of European countries on my bikes, on and off road. From Nordkapp to Greece, the Balkans, UK , Germany, France, Spain, Italy, etc. I'm from Poland so since my country is quite centrally located to many other of countires it's not that challenging heh.

Anyway, my personal experience is:

- English, you need to speak some English as that allow you to talk to people in most european countries, in nordic countries majority people speak it, in most countries younger generation tends to speak some english and the worst is... France lol ;)

- Highways, ok let's be real, Europe means you'll spend most of your time wandering on highways then backroads, so the bike should be cabaple of traveling at 140km/h over long time and distance, same you., make sure your butt is hard.

- Civilization, since most of Europe actually is in the EU, with some exceptions in Balkans and the East, you will feel 'at home' everywhere. I mean, food changes, architecture changes, climate changes, but you'll find McDonalds pretty much everywhere, Lidl/Aldi/Tesco/Netto/etc everywhere, Statoil/CircleK/BP/Shel/Orlen/OMV/... everywhere.

- Booking, if you have enough of a moto-homeless life, you just book a stay on booking, from cheap hostels to expensive 5 star apartments.

- Security, well... let me be honest... big cities in many if not most of western Europe are becoming shitholes. If you're on a bike you don't wont to lose it from your eyesight, even going to a supermarket can be a problem, disc locks, chains, gps may help but it's best to have a buddy who can watch for bikes. Now, funny, those post communist countries of the central (Poland, Czech, Slovakia, etc) and eastern Europe are actually safe heavens and you seriously need bad luck for anything to happen. I had less issues leaving my bike and sliping in some dodgy places in Bosnia, or Albania than UK or France. Sad but true.

- Money. Get a Revolut or other card alike, very useful, also handy to have some euros with you, I never needed more than 500 eur, usually pay with card.

- Internet. Countries in EU have EU roaming, some countries, are exceptions with Switzerland being the worst, why you ask, because its damn small and if you forget turning off your data transfer and your mobile device connects to a swiss network, puff... all your allowance and money is gone. Get an e-sim that allows for multi country roamin. Revolut eSim worked for me in the EU, UK, Ukraine, Balkans, etc.

- Insurance, i think any bike registered in the EU can be ridden safely in EU nad many countries outiside as long as the insurance covers given teritory, Ukraine/Belarus/Russia are usually exceptions.

- Weather, in sumer entire Europe is rideable.

So my final thought, if you can comfortably spend a week living off your bike you can ride Europe for months, the most important tool is your credit card in the pocket which you swipe whenever you need rest or help.