Did C2C in June/July 2016. Was all set to do it in 2015 but had to cancel a month before I was due to set off due to a heart attack. The walk can be as hard as you make it. It is not a National Trail and, as Wainwright says, the object is to walk from St Bees to Robin Hoods Bay. If you do that then you have walked the C2C! That said take a good look at the route. The Lake District is the toughest part and I would highly recommend a stop at Grasmere rather than doing Rosthwaite to Patterdale in one go. I also avoided Kidsty Pike by going around Ullswater to Bampton Grange (which is where I spent a night) There are other sections where there are similar high or low routes depending on how you feel. In my late sixties, two heart attacks, and only twelve months after angioplasty I found the walk very 'doable' and am seriously considering doing it again in 2018. No need to be nervous and I am sure you will have a great time.