Near Orvieto there is always Puglia for chocolate and then on to Assisi which has a beautiful cathedral perched on top of the hill.
If you are there through the first week of June, the Infiorate in Spello is not far from there and really is quite amazing.
http://infioratespello.it/ The streets of the town are turned into enormous murals using flower petals.
Further afield, Ravenna has beautiful mosaics. Urbino is a lovely little town with a very old and prestigious university as well as a Raphael museum.
The valley above Merano up to the Austrian border is lovely. Take a bike on the train up to the top of the valley and ride back down through the orchards on a well maintained bike path that has lots of cafes and bars.
If you get up to Emilia-Romagna, they have the best food. (Probably a controversial opinion)
A lot of suggestions depend on whether you have a car or are relying on trains. San Gimigano is tough to get to without a car for example.