Re #1: It's not that simple.
M-W lists: traveled or travelled; traveling or travelling.
AHD indicates: trav·eled, trav·el·ing, trav·els or trav·elled or trav·el·ling
Oxford shows only the versions with two l's
So, if someone insists that "travelled" is incorrect in AE, they are off base. On the other hand, Oxford's entry would indicate that "traveled" isn't used in BE. Fussy Brits! ;-)
(Of course, my AE spell check is complaining about the double l's here.)
The order of the entries would tend to indicate that "traveled" is more common, but joining them with "or" tends to indicate that they are both acceptable.(Yes, we were actually taught how to decode dictionary entries in school.)
Some older Americans complain about the loss of an "l" in such words. I don't remember what we were taught, but I'm not that young, either. Frankly, I can never remember which is right, so I tend to look it up.
Edit: Typo corrected thanks to penguin.