Dave's travel bags
First you have to see Dave's bicycle and trailer and read his explanation.

"This is my bike/trailer setup for the trip. Bike is a 26" (foldable) Montague. Trailer is home-made. The bike is new and untested, but I probably have around 5000 miles on the trailer."
Well, this bag

is in fact the bag you see on the trailer and somehow he was able to get the bike, the trailer, and all his gear in that bag.
How? Something like this:

Dave has found he can stuff his tent, sleeping bag, clothes, etc. in/around bike parts.
Why all this? This way he can carry his stuffs when he has to travel by bus or by train. Cause in Romania the greatest trouble for a biker is traveling with the bike, not on the bike.