[dredmorbius]

You're right. I'd underestimated crossing times, though prevailing winds also cut time to as little as 43 hours eastward. From Wikipedia's page on the Hindenberg (unattributed):

"The ten westward trips that season took 53 to 78 hours and eastward took 43 to 61 hours."

Given that high-speed land-based rail would be an option, the ferry-to-rail option seems a strong contender, actually.

Remember: the whole concept of moving any significant distance at a rate of more than a few miles an hour is quite modern.