A few general questions about overland segments:
1. Is there any way to do the Trans-Siberian railway on OWE? I'd like to do it on my next trip. I vaguely recall you can't do an overland transcontinental journey. I guess you could do a return trip :-)
1a. What is the closest OW hub to the eastern end of the Trans-Siberian?
2. Is it possible to do an overland *instead* of an already booked segment? For instance, my upcoming OWE I fly from Santiago to Buenos Aires. If I decided on a whim to do this overland (which I might) and forego the flight, can I just pick up my itinerary in EZE without penalty?