In reply to jack_44: I did JOGLE in summer 2011.
There are a number of ways to skin this cat and you will need to tailor the advice to the way you intend to do it.
1. Fully Self Supported (Camping) - will be the cheapest but will take the longest as you have to carry tents, sleeping bags, cooking gear etc. On day 2 I met a guy on an ancient hybrid type bike with only 3 gears and a plastic box cable tied to his handlebars. He managed it on the cheap but it took a fair few weeks. We also met a couple in Carlisle who were fully loaded and had taken 2 weeks to get there from JOG! needless to say they had run out of holiday and had to go home without finishing.
2. Full Support - a support vehicle carrying all your stuff, either camping or staying in b&b's, travel lodges or camping. Cost varies, but will be much faster (which helps keep cost down) as you don't have to carry anything. Problems are you need a support driver whos prepared to take a substantial amount of time off work just to watch and prepared to drive a lot.
3. The Credit Card Jogle (what we did) - No support vehicle, but we stayed in a mix of B&Bs, travel lodges, hostels etc. Average accommodation was about £40 - £45 for the room split between 2. Eating out in pubs etc, plus day food, actually cost a fortune....I reckon the two of us probably spent about £900 on food in ten days (£50 evening meal and drinks, deserts etc + £15 on lunch in café + £15 on sweets, chocolate, falpjacks, monster energy drinks etc. With trains, I reckon we spent close on £2k for the total trip, accommodation, food, drink and trains from start to finish. but we weren't frugal, we just bought whatever we wanted. We carried a bar bag and a rack bag with flipflops, night-time t-shirt and shorts, tooth brush, wet jacket. I wore the same cycling shorts all week as I could wash them in the sink and dry them overnight. The only other bits were inner tubes and a basic tool kit and pump. We did it on racers which was far better as you can go much faster and get the distance covered quicker each day and then rest. 8 hours in the saddle is better than 12 hours in the saddle because its not your legs that hut, but your neck and wrists and arse.
If I were to do it again I would try and get a support van. That way you can camp and cook your own food which would be the best balance of speed and low cost. But you need someone to do it.
Training - I had never ridden a road bike until 6 weeks before I did it. Its not physically demanding, more mentally boring. Its actually quite mundane spending 8 hours spinning your legs with ulcers in your mouth from all the food your eating. The most important part of training is getting your bum ready for it.
I can see why it appeals to retired people as they have much more time to actually spend some time at the places they're passing through. If your doing it in < 2 weeks its actually pretty much a heads down and crack on affair.
The only other thing I would say is get a descent bike that is in good order and unlikely to break down. People have done it on a skateboard, a unicycle etc so don't listen to the people who work in bike shops. If I had a tenner for everytime a bike shop assistant told me I couldn't do Jogle on my bike Id be a very rich man. Funnily enough, none of them had ever done it themselves.