The breast cancer one, is the one I’d concentrate your efforts on, if it were me, given I’m a very experienced, trained British Cycling ride leader, who specialises in getting people from newbie to 100 mile challenge rides, in relatively short spaces of time, as it’s more geared to getting you to your mileage goal. The C.R. one is a bit too vague, and not structured enough. Interestingly, the Breast Cancer one, starts at a 5 mile effort, which I’d agree with.
Here are some pics of me leading this sort of challenge training ride, for the charity Scope, a couple of years ago.
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and here’s another group I got up to multiple 100 mile days, from beginners on a charity ride I did from Huddersfield to Southampton last year.
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I’ve done lots of this sort of training / training plans over the years, and I’d definitely say the Breast Cancer plan you linked to is the better of the two.
Have a look at the Ride London site for their training plans, and maybe on the British cycling website too. They are all very useful resources.