Mugello on Sunday, IOM before Wednesday race day might be a little ambitious!! Ferry tickets to the Island book up very quickly, although tickets sailing out mid race week usually available for a few weeks from release of bookings (which still means booking during June 2018 for 2019 sailing), tickets back to the main land Saturday or Sunday after the Senior on Friday are usually sold out on the first day that bookings are made available. I would definitely recommend getting your sailings booked before making any other arrangements (everything else, bikes, accommodation etc will have a solution, but without ferry tickets.............). Or do the Classic TT/Manx GP instead, still needs to be booked early October for following year but achievable. Combine with British GP (though you would miss the classic racing) or earlier/later European GP to extend your holiday. If the bug bites after watching the Manx, you will definitely abandon everything else and focus everything on getting ferry tickets for the TT, like the rest of us have to every May before the next years TT!!!!!!!!