Hi.
Never done the coast to coast but have done a couple of weeks backpacking in the highlands of scotland. Started out from Fort William and eventually ended up on sky. Deffently agree with you Foxy mars about keeping your pack light! Really enjoyed the wild camping and the nature you saw. My one draw back was the coach journey there. From Norwich- London - Glasgow - Fort William took 17 hours with the wait for connections! Put me off doing it again!!!
Have a good time.