Has anyone done the South Downs Double or a similar off road endurance route? How big a step up will it be from 100 miles?
What sort of time do you think you'd have to be capable of one way to be able to complete the double, and how would times compare?
Any tips for training, nutrition, start times etc?
I want to have a crack some time, but just wondering if it's possible and what time I should target? I've just done a 7:47 one way.