Just went for a three day ride in Denmark, from Helsingør down to and trough Copenhagen. Went there by bus (from home to the ferry) and boat/ferry to Copenhagen and then train from Copenhagen to Helsingør. We used foldingbikes and had most of the stuff (including sleepingbags and tent) in big backpacks "hanging" from the handlebars and strapped to the frontracks (where most of the weight went). Had just some light bags on the rear racks on two bikes.
It worked ok, but the bikes carried all the weight (rider plus lugage) plus parking the bike for visiting museums and such was a bit complicated, we ended up taking turns watching the bikes.
This trip made me (again) think about traveling with trailers, like the Bike Fridays Samsonlite trailer, the Carry Freedom City trailer or the new one from Burly, all small wheel trailers (12,5") so that they can easely be detatched from the bike and rolled innside buildings, shops and so on.
How do you carry your luggage when touring (similar type trips) on a folder?