Duluth/Superior International Airport (DLH) is served by Delta and United with direct flights from Minneapolis/St Paul (MSP), Detroit (DTW) and Chicago (ORD).
When you arrive, you can rent a car, or use shuttle for both The Inn on Lake Superior and Radisson Hotel (Voyageur Lakewalk Inn has no shuttle). There are many taxi cab companies, and both Uber and Lyft have pretty good coverage with short wait times. Finally, there is a city bus line and another one.
Alternately, if you want to fly to Minneapolis/St Paul (MSP) only, you can take the Skyline Shuttle or drive (about 2 hours 30 minutes).
To get from your hotel to campus, you can use the hotel shuttle. Currently, we are unable to provide transportation to workshop participants between the UMD campus and downtown.