You can zip from Paris to Strasbourg on a high-speed train in less than 2.5 hours. Other major European cities also offer train connections, many on high-speed trains. Night connections are the least expensive, but expect to spend between €55-€100 for a one-way ticket.
Once you’re in Strasbourg, you easily can travel to Sélestat, Colmar, and Mulhouse by train in less than an hour. All of these towns have modern public transportation systems in place for traveling throughout the region.