Isn't that radio conversion or operationg thingy included in the FAA PPL license? I know there are some differences between US and EU (like requiring start up), etc... I had a chance to sit with an instructor for sim session and he was always correcting the way I said some stuff cause it was to U.S (fsim fault)...
I also find that US flying less restricted than EU, for example, in Germany it seems it's necessary to always have someone operating in the airport if there is any flight... In US they have "uncontrolled" airports... etc... The airspaces, airspace rules and airways are different it seems.. I don't think it will be hard to adapt though I heard many people complain that EU flying (special when near big airports) is very restricted and frustating. Same happens with fligh plans, etc...
But it will be a matter of getting use...