Mobile Abroad

So...I was asked a day ago to fly to Milan to go through 2 days of training on a new product. I need to have at least a data on my phone for the 6 days I will be in Europe, but am looking for the least expensive option.

I have a Sprint iPhone 4S. They will unlock my phone for the trip, or they will change me over to the international plan.

Right now the plan is to fly into Malpensa Airport and take a train to Milano Centrale on Tuesday, go to training Wednesday & Thursday, then hop a night train Thurday night to Traunstein, Germany to meet a friend.

Any suggestions?