By ship
There are some cruise trips from Koblenz to Trier. However: they are expensive.
By train
Trains leave hourly from Trier to Saarbrücken, Koblenz and Cologne. Timetable and ticket information could found at (http://www.db.de/site/bah...)
By car
Trier is connected by the European motorway E44 from Luxembourg city ~50 km via Trier to Koblenz ~100 km, E422 from Trier to Saarbrücken ~100 km.
Trier is connected to the Autobahn A6. This city is about one hour from Kaiserslautern or two hours from Mannheim.
By plane
There are several airports in the vicinity with reasonable access to Trier.
Luxembourg Airport is about 50 km away.
Low-cost carrier hub Frankfurt-Hahn is 75 km east of Trier. There are roughly-hourly Flibco (http://www.klikhierniet.nl/) buses, but the bus stop is several km out of town near the Nell's Park hotel.
Frankfurt International Airport is about 200 km away. The train from there would be about 3 hours via Saarbrücken or Koblenz.