My longest trip has been Madrid-Brussels: 1580km to go and 1700 km to return (avoiding Paris) , two days, with my girlfriend as pillion and the bike fully loaded with soft cases. We are pretty tall so there wasn't too much space. She felt pain in her knees. The French messed up with trucks stopped with the engines off for more than a hundred km for no reason that I know, it was summer and we were wearing black leathers. Lots of sweat. No Hotel reservations, so we were lucky we found one just next to the highway in the middle of France. When I arrived to Brussels I get lost looking for the place where we had to work that very evening doing porn.
It was insane but we loved it. Crazy times.