Well, Venice is amazing... saying it's like Disney land is a bit harsh, but do try to avoid it mid season, early spring can be nice, but getting there on the bike may be a bit chilly at that time.
I have to say that Croatia is pretty nice, run down the coast to Split and beyond and you'll find some wonderful places, you could then get the day ferry to Venice, leave your bikes at your hotel and sail directly to Venice. It would be my preference.
Mugello, the atmosphere can be incredible... last year wasn't so good as Rossi never stood a chance on the Ducati and the ticket prices are very high; they were talking of dropping them as they have done in Spain, but as the track is owned and operated by Ferrari, we'll have to see, but the crowd when it's the right size has a wondeful buzz and if Rossi is up there, then expect tingles..
Misano was one of the worst Moto-GP experiences in 20+ years of going.. the crowd is super aggressive, there's very few stands and the banking is a free for all, it's more akin to a football match than a GP, there's nowhere to park and you pay residents to park in their front gardens! and the racing was pretty poor... I only live an hour and a half from there and would never go back..
Imola for WSBK was fantastic in comparison, great crowd, great track to watch at and close to Bologna if you want a great place to stay... food and wine etc... watch out for the 'working girls' on the way to the Ducati factory though... don't stay too long at the traffic lights...