The Traverse City airport (TVC) is a small regional airport with several daily flights to and from connecting hubs in Chicago and Detroit. It is only a short (10 minute) shuttle ride from the airport to the hotel.
The Gerald R Ford airport in Grand Rapids (GRR) is a 2.5 hour drive from the hotel. It has more options for flights to connecting hubs, but you will need to rent a car or coordinate with others to reach the workshop from the airport. Contact the workshop organizers in that case.
The Capital Region airport (LAN) is a 3.25 hour drive from the hotel. Similar to GRR, it has more options for flights to connecting hubs. This airport serves Michigan State University; contact one of the MSU workshop attendees if you want to ride together from the Lansing area to the workshop.
The Detroit metro airport (DTW) is a major airline hub and the first point of entry for many travelers to the US, especially for Delta Airlines and the SkyTeam alliance partners. It takes over 4 hours to drive from DTW to the workhsop hotel. It will be much easier for you to book a connecting flight from Detroit to Traverse City.
Similar to DTW, the Chicago O'Hare airport (ORD) is also a major airline hub and a first point of entry for many travelers to the US, especially for United Airlines and the Star Alliance partners. It takes over 5 hours to drive from ORD to the workhsop hotel. It will be much easier for you to book a connecting flight from Chicago to Traverse City.
If you come from Michigan or nearby, then the easiest transport option is your own car. For example, driving from Chicago or Fermilab or O'Hare airport to Traverse City takes a little over 5 hours.
Greyhound and Amtrak connect Traverse City with other bus and train routes in Michigan and beyond. The BATA bus terminal is only 1.1 miles (2 km) from the hotel. Expect the bus ride to take many hours but be affordable. For example, the route Chicago Union Station to Grand Rapids (by train) to Traverse City (by bus) goes along the lake, but takes 12 hours. There is no direct train service.