I am getting ready to book some group tours in Rome during the third week of May, and one is a 3.5 hour tour of the Colosseum/Forum/Palatine Hill at either 8:30 or 1:30. I know that weather is unpredictable, but is it likely to be hot enough in the afternoon to make the 1:30 time less desirable? (We live in a hot climate, so I would be thinking of at least mid 80's -90's as hot.) Or would it be significantly more crowded in the afternoon? The morning tour is currently only available on Saturday, and we have penciled in a day trip to Orvieto from Rome on Saturday since there is a market there in the morning. We could switch Orvieto to Thursday, Friday, or Sunday if we would be better off doing the morning tour of the Colosseum. Are any of these days in Orvieto likely to be more or less crowded?
Also, Rick Steves suggests taking the bus from Orvieto to Civita and Bagnoregio (although I think I read there is no bus service on Sunday). Are these worth creating a long and perhaps too busy day or would we be better advised to spend more time in Orvieto?
I look forward to those who can share their experiences. Thanks!