Isn't it common to throw an extra off day in there when there's travel involved? Especially this much distance between host cities
Pretty much, at least back through 2016. Even when the Pens and Preds played, they had two off days when they traveled. There are a few years they had two off days between games one and two, but I assumed that was an arena scheduling thing.
My guess is the league is trying to minimize the impact of travel fatigue on the finals. These guys have basically been playing every-other night for six or seven weeks at this point, with the exception of any break they get by finishing a series early. Having to win four best-of-sevens is already a battle of attrition. This year happens to be extreme on travel distance, vs. something like the Pens/Pres, Black Hawks/Bruins or Flyers, Blues/Bruins.
The NBA does the same thing. In fact, for years the NBA Finals best of seven was a 2-3-2 sequence to minimize the impacts (goes back to the yearly Celtics/Lakers Finals), but they decided that change diminished the advantage that the higher seed had so they switched back.
It's tougher on us fans, but I think I see the point. The cumulative effects of travel have little to do with the condition these guys are in. Even the best conditioned athletes or people who travel almost constantly know how it effs up sleep patterns and such.
For me, the withdrawal of going from one or more playoff games every night to having nights of no games is worse than an extra one to three days to get through the finals.