Nobody- and I mean nobody- is going to stand at Kirkby Stephen station for an hour to wait for a bus.
The traffic, such as it is on a Sunday, is going to be from people in Kirkby Stephen, Brough, and Appleby going into Penrith.
Both the bus and the train services are, certainly on a Sunday, rural services at a very low frequency. Unless you build the bus timetable based on the train times at Kirkby Stephen then any connections are going to be purely accidental and there's no point running the bus up the hill for that. And having the service dictated by the trains at Kirkby Stephen would, in my opinion, really be about the tail wagging the dog.
It's a very different situation to the buses at Garsdale which are designed to connect to the trains. Those buses' purpose is to take tourists to Hawes.