On the classic west-to-east itinerary, Rosthwaite is the second overnight stage stop, following Ennerdale Bridge. The Ennerdale Bridge to Rosthwaite stage is around 15 miles / 24km on commonly used itineraries, with significant ascent and descent through the Lake District fells.
That makes The Royal Oak a particularly well-timed overnight stop: by the time you reach us, you have already completed two substantial Lake District stages and have another significant day over Greenup Edge ahead.