Really good advice and input so far.
I chose a BOB trailer for a few reasons:
Mt. tandem with suspension fork didn't accommodate front panniers.
Don't like the totally overloaded rear pannier setup.
The trailer seemed like a great way to keep tons of weight off the bike.
Touring offroad meant encountering bumps, ruts & rough terrain; thought it be better to do so without an overloaded tandem.
Industry deal made the BOB a financially reasonable solution.
Plus I liked the idea of having a trailer for my single bike as well for shopping trips.
We didn't have dedicated, lightweight touring gear, so we couldn't compress it into a manageable size.
We did meet a single bike tourer who overloaded his BOB, got high speed wobble and crashed HARD. He had MAJOR road rash and scars to prove it. So if you go with a trailer, respect the max weight limit. (Although a tandem should be better able to withstand high-speed wobble issues. Then again, the consequence of a crash is twice [or more] as bad!)
This was 20 years ago, before the proliferation of extensive use of frame, handlebar & seatpost bike packing.
You could start "small" by choosing some frame bags and starting with credit card touring to see how things go. Decide how much you like it and how much you intend to invest in lightweight touring gear.
Either way, touring by tandem is so ideal. No getting separated. Working together as a team the entire tour. Conversation and being able to enjoy things together.