They rented two cars, San Fransisco was their starting city(California was naturally a place of interest for people studying underground construction, with San Andreas shift being there and all). I don't exactly remember all the places they went, but they visited many US mines. San Fransisco, Salt Lake City... where are those big mines of the US anyway? It was a from west coast to west coast sort of trip, taking U turn in the middle of USA or something like that. It was a fun trip from what I've heard and the bad food was pretty much the downside of USA in his opinion. I don't know if the bad food was ubiquitous in his US trip and he would probably know the full story better.