Realistically, being a Delta wh@re myself, the usual routing to Asia on Delta, is West not via Europe. Almost impossible to book a random ticket to Asia from the US on Delta, and have it transit via Europe. So….. if Japan/China is the first actual point to clear customs, it's a very circuitous routing on Delta. Again, not to say that you CAN'T get there that way, but almost any attempt online to book a ticket on Delta to Japan/China will route you through their NARITA hub (japan) or LAX. Tampa>Detroit>Amsterdam>XXXXXX is almost certainly a routing to India or SOCHI, and with all the clues related to Frozen and Snow, I am still certain that Sochi and the WINTER Olympics are the destination. The trip would have been booked long before it became evident that Sochi Park wouldn't open for the games. If that was the only thing they were doing, then they could cancel/rebook, however if they had booked anything for the games themselves (CLOSING CEREMONY at USD$1,000 on more per ticket) then, there's no canceling/rescheduling that, and you just go and forget the coasters and enjoy the (perhaps) once in a lifetime Olympics experience.
oh, the rent logo, in olympic colors is another clue to add to what I've already listed. The DEVO album cover, also in the 5 Olympic colors, again points to SOCHI. Have to admit I don't get the "YOU SUCK" Scott Pilgrim picture, but I do see that it says "you suck". The Ferris Wheels are a big Ring, again an Olympics hint.
Also, it's totally likely that Rob has programmed certain posts to happen while they are in air, thus throwing people off as to where they were when the Tampa airport pic and others were posted. (especially on the DET-AMS leg of the trip).