As for the age-old debate about panniers vs. a trailer, there is no correct side.
Some considerations assuming, for the sake of discussion, a B.O.B./B.O.B.-style trailer:
If you take your bag(g) inside the tent, you have one bag with the trailer, more (usually 4) with panniers.
The trailer can make it easier to make a grocery or firewood run using the bike. No need to make space in your bag or panniers. During our group x-country tour we found a trailer extremely useful for carrying 30-paks back to camp from the store.
Without a trailer, there is one less item that might have to be boxed and shipped or might cost you an oversized baggage fee.
Less wind resistance with a trailer. However, you don't have panniers to act like sails when you have a strong tailwind.
Some have trouble sometimes fiding parking space for and/or turning the longer bike-trailer rig.
If your tariler bag isn't compartmentalized. you may want/have to do a little more organizational work, such as keeping things in ditty bags or individual stuff sacks. My panniers have adjutables "walls" inside the main compartments that allow me to create segregated spaces if I want to. I happen to like that since, by nature, I am generally a disorganized person when it comes to physical items.