I will be traveling mid May and will be in Orvieto for 2 days and Rome for 2 days. What are some must see's and do's while I'm in the area. I will be staying in Hotel Duomo in Orvieto and Hotel Giulio Cesare in Rome.
Well your itinerary is a bit off the track for me, just a bit more familiar with Tuscany! However, Orvieto happens to be one of my more favorite non Tuscan towns
1) the well of San Patrizio is a fun visit as is the underground carvens in Orvieto
2) another place I have visited nearby is Civita di Bagnoregio, a lovely little town only 24 kms from Orvieto. This is really better if you have a car and while your at it then you can visit one or two of the vineyards in the area.
However if you are not going to have a car, you may just want to consider one day in Orvieto and then visit Arezzo or Florence Both are easily reached by train.