Tired legs after such a short space of time?
That kind of statement doesn't read like someone adequately prepared for a year long challenge. 100 miles a day isn't that far, given the context. I expect she will cycle herself into form, but the statement does make me wonder if her body will rebel.
Most randonneurs will be familiar with the fatigue that sets in if you aren't conditioned to long rides, particularly if you are riding further than usual or you are stacking up rides one after the other. My rule of thumb is that if you aren't conditioned, you ideally need #kms / 100 days rest between rides. I hope she doesn't get the arse, hand, neck, feet and knee problems that can come with riding too much without building up adequately.