I'm also doing this as part of my GNR training. Had a look at the results from last year and don't think I'll come last (!) but it's my first truly hilly race so I am a little nervous!!
Same here Kate we have been doing some hilly 10 mile runs in training but still probably nothing like the hills over those first 4 miles in Chesterfield.
Just have to take it easy at first and then try and make up time from 5 miles onwards.
I am not really trying for a good time in this one just happy to get round as if we can do this then we will be ready for the GNR.