Do not worry about hills. There is no hill that can not be walked. Coming last not possible! That is my position. I was last man in on Sunday's Beat the Bore and can not wait for the September race. We were saved by the freezing temp because the mud was frozen solid! If it rained and if it was a bit warmer it would have been a muddy slog!
I agree that £21 for 10Km is too high. The mixed terrain runs are a bit tougher, but less traffic and more enjoyable and you get to see nice scenery too.