Tony, you've just opened a monumental can of worms that I can only tip my hat to you for taking on.
We leave next Wed LEJOG, we decided to go mid April, since then I've picked up all I know from this forum (not that that's alot mind!), lots of very clued up folks on here and more importantly happy to help.
You'll get many different routes offered - really the route is time dependant and how many miles you want to do daily and what type of roads you'd prefer. We're going LE-Okehampton-Bristol-Ludlow-Chorley-Carlisle-Edinburgh-Newtonmore-Tain-JOG, direct over 9 days (lots of people would bemoan this route as they like to miss the main roads but we only have a 9 day window available). Obviously you have the peaks to throw in. Then are you going JOGLE or LEJOG - I've done the 3 peak challenge and we did Ben Nevis last which was a real ba****d, do you want to leave that till the end?
What you propose is a massive challenge, if I can help with any specific advice please private mail me - I found you get good advice if your question is quite specific and not too general, but all the knowledge is here, it's just asking the right questions.
Best of luck.
Robbie