Flights: There are flights to Zurich or from different cities in the U.S. and other countries via different airlines with a train connection to Luzern. There also train from several major cities in Europe to Luzern.
Swiss site: https://www.sbb.ch/en
• Zurich to Luzern—-40-50 min—Appx: CHF 12.50/one way
Climate: The weather at the end of June varies from 74 / 56 F
Currency: Swiss Franc (CHF)–1 CHF about $1.09, 0.93 Euro
Visa Requirements: At this point in time, the U.S. passport holders do not need a visa for a short stay (3 months) in the Swiss. For the EU countries no visa, and other countries, please visit the site: https://www.schengenvisainfo.com/switzerland-visa/