On the 14th April, I hiked from Rosthwaite to Carlisle. I hiked the whole of the Cumbria Way, north to south a few years ago. A few people have commented that the stretch from Carlisle to Caldbeck is rather boring, personally, I don't agree. I agree that the section from Carlisle to Dalston is a bit bland but from the Bridge End Inn, just beyond Dalston, when going south, the route I believe is fine and as you approach Caldbeck it gets even better. If you camp, there is a small campsite 5 mins from the pub, you walk past it on the way south, £5 a night.
As I walked this time from south to north, I chose when I got to Skiddaw house to turn to the right to get to Caldbeck. There is a choice if you want, you can go to the left, both paths get toi Caldbeck.