Hi
Yes, you certainly do need to do a bit of practice - lots of ups and downs, especially in the Lake District. You may find the following link useful - lots of piccies and an idea of the route etc. Don't forget to wade in the sea at St Bees first, pick up a stone off the beach, carry it with you, then when you reach the other side wade in the sea again and drop the stone!!! My son did it several years ago and loved it, apart from it getting a bit monotonous on the North Yorks Moors! He did feel quite emotional when he finally saw the sea at Robin Hood's Bay after all that trekking - but well worth the effort. Good luck!!
www.byron.pwp.blueyonder.co.uk