The received wisdom is that 'most people' LEJOG, this is in order to enjoy, it is said, the prevailing wind.
Since there is no co-ordinated effort to collate information on End to Enders the received wisdom seems unsubstantiated.
One thing that is universally accepted is that the South West of England is the hardest part of the trip and, of course, there is no way round it. It is also indisputable that the prevailing wind direction is not the exclusive wind direction.
Of course there are other factors to bear in mind - how you plan to get to the start and then back from the end being key among them. All else being equal, though, the question is whether to do the hard bit first and hope for a tailwind; or the hard bit last and risk a headwind?
We LEJOGed and got a headwind across Dartmoor (our third day) where we anticipated a tailwind (the prevailing wind). The effect on morale of feeling completely exhausted and not yet having completed a fifth of the trip should not be underestimated.
How long you want to take may be different to how long you've got.
The shortest route by bike is 874 miles. The record for riding it, just over 43 hours. The Cicerone route is 983 miles, Sustrans about 1200, and ours 975.
There is an organised ride over 9 days (i.e. for 5 days off work). However even by the shortest route that's nearly 100 miles a day and the 9 day period doesn't account for the full day's travel at either end that most people will need.
Fourteen days is the basis for the Cicerone guide (longest day 85 miles). Over a two week holiday that gives room for a day's travel either end. We cycled for 17 days building in one 'short' day (32 miles), and cutting down the distances we had to travel on each day in Cornwall and Devon (in anticipation of their difficulty).
For me much of the enjoyment is in experiencing the country develop at a leisurely speed, so take as long as you can.
By bike, obvs, but you'll need to set some parameters, however arbitrary.
Purists will probably want to ride a single speed bike, carry all their kit, and camp. Those on a tight timetable will need a light bike and a support crew.
The more extreme your approach, the less resilient you will be to the unforeseen, therefore the more prep you will need to do.
An unexpectedly rough surface can ruin a day on a pure road bike. A mechanical on day two of nine could render the whole trip unfeasible.
If you've got three months and you're camping, on the other hand, you can cope with pretty much anything.
This is really best determined after answering the first three questions together with a consideration of the capabilities of the riders you're with and what you all want to get from the trip.
The Cicerone route is efficient, perhaps at the expense of quality of scenery and quantity of road traffic.
Sustrans are almost slaves to quiet roads and traffic free paths.
I think that, whatever route, there is no better investment in time and money than a good bike satnav loaded up with .gpx files that you've created of your route. There is nothing worse than being lost.
This is really important.
There are no stations at either LE or JOG. The nearest station to LE is Penzance and to JOG is Thurso. Services to these stations are not great. The nearest mainline stations are Truro and Inverness respectively.
It is increasingly the case that cyclists are expected to book bikes onto trains. This is free, but slots are limited and often there are no more than two or three on any one service. This makes it difficult if you're in a group of four.
There are taxi services available that'll take you and your bikes between stations and your start / end point. They're not cheap and, generally, require a booking.
Ultimately there is little substitute for having a mate at either end with a car and a bike rack.