The bike with the trailer looks to have mostly fuel on the bike itself. The tank on the TW is small, so it only has a 150 mile or so range. Looks like that big box behind the seat might be a fuel tank, and he has some small jerry cans too. Both bikes are very awesome.
Edit, scratch that, the big box on the bike is storage. I did find a different TW built for expedition use that has a custom fuel tank in the location though.