Quadathlon- Hiking, swimming, cycling and running

A few months ago, i couldn't ride a bike or run long distances due to injuries and problems i had throughout my childhood, but now with a lot of support, my confidence had rapidly grown and i am looking to complete 4 challenges in order to raise money for a couple of charities close to my heart. My challenges i've set myself are- the 3 peaks challenge (Snowdon, Ben Nevis and Scafell Pike) within 24 hours, cycling 100 miles, swimming 1 mile in a pool (60 lengths of a 25 metre pool) and running a half marathon. Does anyone have any training methods they have that could help me keep in shape and build endurance ready for these challenges?

No suggestions, but good for you and good luck!

When I went from not running after 18 months of having an injury that sidelined me to registering for a half marathon, I used one of the iPhone apps that is sort of like the couch to 5k programs. If you have an iPhone or android, search for one of them. They build up your endurance with a mixture of run and walk. It is not right for everyone, but for me, it worked to get me to stick to not pushing myself too soon too fast. I didn't want to re-injure my ankle and the program was doctor approved.