This question deals with the hero Arvel Worldwalker.
Her Hero Ability states the following:
"When you fail an attribute test, you may reroll it. Limit once per round".
When used specifically in a quest, our interpretation of a round is one hero turn, one OL turn.
How, however, does this apply when traveling prior to starting the quest? If, for instance, you are traveling a distance of 4, resulting in 4 travel cards being selected, can she use her Hero Ability once per each travel card requiring an attribute check, or is it just once per travel period, or can she not use it at all while traveling?