Hi
Well I don't know about lists of routes but I did LE-JOG on a Royal Enfield some years ago so I may be able to help with suggestions.
First thing to decide is how long you are putting aside to do it in. If you want to get there in one or two days, you can easily do it but your route will have to be fairly direct or your days long.
Second thing to decide is the smallest and the largest type of roads you want to use. I avoid motorways wherever possible as a matter of principle and certainly for this sort of trip would suggest they negate the point of it. However if you want to do the whole thing on unclassifieds, you may be in for a difficult trip (and some hellish planning!)
The hotel at LE itself is (or was anyhow) a bit pricey but I figured it was the right place to start from & it certainly gives atmosphere to just walk out, start up and amble 50 yards to the sign for the off.
I can give you some recommended roads that you could include in your route if you like.
The coastal road to St Ives is amusing but there's nothing dead special about anything (road-wise) down in the immediate area of LE. Or Cornwall, IMO. Of course, don't forget to nip down
The Lizard for the actual most Southern part of the UK mainland.
It's worth (if you feel like visiting things en-route) seeing if
the transatlantic hut is open.
Avoiding Dartmoor would be a little mad as while the roads aren't 100% classics, they are pretty nice and anyhow Dartmoor's well worth seeing in its own right. IIRC Wallabrook - Bovey Tracey is a nice amble.
From there, unless you have a pressing reason to visit London or Birmingham, I'd head over to Bristol and thence into Wales. Take advantage of the excellent roads up through Wales to come out at Oswestry, head across under Stoke and to Ashbourne. From there I can heartily recommend the A515 (in fact its an ace road all the way from Litchfield). I'd jump off at Chelmorton and go visit
the plague village of Eyam. Beautiful and interesting.
From there there's the ever-famous Snake Pass to Glossop or (if you've got a proper pair of b*llocks on you
) go right on the A57 from Ladybower reservoir and a few miles later go left and take Mortimer Road all the way to the A616. Mind those up-hill, off camber hairpins though!
At this point you really have to just belt past the Leeds / Bradford conurbation to get to Skipton. From there the A59 takes you East until you see signs for
Bolton Abbey. Well worth a visit if you have the time. If not, just stay on the stunning B6160 to Grassington (another pretty town). When you get to the village of Buckden then you can stay on that road but if you want to see some of the most spectacular scenery in Britain and ride my personal favourite road, turn left for Hubberholme and Oughtershaw. This road leads you over and down to Hawes. Nice place. Good cheese. Its worth visiting
the Green Dragon in Hardraw to see the waterfall ('Hardraw Force').
Going from there up over Buttertubs to Thwaite and East along the B6270 to Richmond is rewarding, lines you up nicely for the trip North and as a bonus lets you visit
Altberg 
North to Barnard's Castle will allow you to avoid the A68 for a while but eventually you have to join it. This'll take you towards Edinburgh but the turn off to Peebles is rewarding.
There's no easy way of avoiding the built-up area between Glasgow and Edinburgh so you could just belt between them and get it over and done with. Mind you, if you've time I'd say that bimbling over to Irvine would allow you to go up the coast to Greenock. There's
a ferry you can get across to Dunoon and from there you have the A815 and A89 over to the West. And if you're going out that way, you are an utter fool to miss out on the A861 through Strontian and then the coast hugging minor road to
Ardnamurchan Point. Most Westerly place in the United Kingdom mainland and utterly spectacular. I'd go a very long way out of my way to ride that road & visit that place again. Superb.
The A82 to inverness gives you the perfect chance to join the A9 there. Stay on it until the A99 goes East to Wick and join that road. Both are very rewarding indeed. When you get to John O'Groats, enjoy it but then go to the actual most Northerly place in the United Kingdom mainland at
Dunnet Head. It isn't far away.
Thurso is worth a visit - nothing exciting about it, but its a typical Northern Scottish town and isn't as bleak as JO'G which (frankly) is a bit awful.
And there you are - LE-JOG. Hope this was of help. Blimey, I wish I was doing it meself now. Maybe next year
