I do a little recreational cycling in good weather, and almost nothing during the winter. I have never done anything on this scale before. A long cycle ride for me was 10 miles. I have to re-adjust my scale - 70 miles needs to be my new 'medium' distance.
I'm not sure exactly what training is required, so given that I only have a month before the ride, I am basically cycling as much as I possibly can. At the time of writing (late June), I can easily sustain 30 miles a day (hopefully at about 12-15 mph - I haven't installed the cycle computer yet) on flat to slightly hilly terrain (I live in Cambridge). I'm increasing the mileage slightly every few days. I have to take a day off once a week or so due to work commitments, which probably helps a bit.
I try to cycle at a quick pace, so if my legs don't feel tired, I speed up slightly. I find that a faster pedaling speed of around 60 to 90 pedal rotations per minute to be efficient, if slightly comical to watch. I'm also starting to add some weight to the bike so the training is more like it will be during the ride. Cycling with heavy panniers is very different than cycling without, but no more difficult - just a bit slower. The bike seems more stable with the weight for some reason, and because of this and the added resistance, it's easier to get into a rhythm.
Nutrition
I don't know much about nutrition, but thanks to Google, the concensus seems to be to eat plenty of carbohydrates and stay hydrated. Things like porridge, pasta, potates and other vegetables seem to be working. I am cutting down on tea and coffee, as well as sugary and fatty foods. I have noticed that eating a banana before a ride gives me an energy boost. I haven't resorted to specialist energy drinks or snack bars, but then I'm still only cycling less than half of what will be doing in three weeks time when I start the actual ride.
On a warm day, I find I need to drink about 800 ml of water an hour - that's one cycle bottle an hour. So with the capacity to hold two 800 ml bottles on the bike with a third in a bag, I can go three hours without topping up. When I get back from a training ride I drink as much water as I can, and after a short while I'm back to normal again.
Clothing
What you wear doesn't seem that important, and it isn't for short bicycle rides. But for rides above 20 miles, the wrong clothes leave me too hot, sweaty and uncomfortable. Cycling shorts make a huge difference in terms of overall comfort and heat dissapation, as well as making the saddle bearable. Cotton t-shirts are stifling when the temperature is high, so I'll have to investigate more specialist upper body attire designed to allow the body to breath.
Staring at the sun's reflection on a road for several hours gives me a headache without sunglasses. So I bought a pair of cheap polarised sunglasses which help immensely. They are a good fit around my eye sockets and also help keep flies out of my eyes. Whilst slightly more expensive than non-polarised lenses, my polarised sunglasses do help to cut down on reflections on car windows, so it's easier to see through a car at a junction, for example.
I am reluctant to buy clothing items that can only be used for cycling, so when looking for footwear, I avoided cycling shoes and instead ended up buying cheap lightweight walking shoes. You can feel the air circulating when cycling which is good. They also provide excellent grip to the metal pedals of my bike. When it's really hot, I just wear sandles.
