Travel
Castelpietra is located few minutes away from the town of Trento. Trento can be reached by train from either Milan or Venice with a train change in Verona (the whole trip will take around 3 hours). You should be able to reserve your train about four months before the wedding at this site: https://www.trenitalia.com/en.html
If you decide to rent a car, Trento can be reached from both Milan and Venice in about 2-3 hours depending on traffic. Most of the way is highway.
Below are some suggestions for hotels. These are just some starting places, so absolutely feel free to choose another hotel, AirBnB, or other accommodation if you prefer.
Shuttle buses will be provided from the Grand Hotel Trento to the castle and back for guests coming from the United States.