Drawing on a post from last year: route choice, in a 'macro' sense.
The main choke points on an end-to-end are: N/S of Bodmin Moor, Bridgwater, crossing the Mersey (Widnes or Warrington), Preston and Carlisle.
Routes to Bridgwater are broadly 4:
1) Keeping south past St Austell, Fowey ferry, Plymouth/Tavistock and over or north of Dartmoor
2) Head for Bodmin paralleling A30, skirting Bodmin Moor via Minions, Horsebridge and Tavistock,and over or north of Dartmoor
3) Head for Wadebridge and A39 north of Bodmin Moor, to Davidstow and then either cut east to Launceston and the old A30 to Exeter, or 4) from Davidstow take the 'high line' via Holsworthy and then either Torrington, and B3227 to Taunton or Hatherleigh and ENE (various options).
From Bridgwater north: either over Avon or Clifton Suspension bridges, and then either up (or parallel to) A38 (Gloucester and north/Severn valley) or across Severn Bridge and Forest of Dean, Hereford and variations north.
North of the Mersey the 'normal' route is to parallel the A6 (with some stretches on it) via Preston to Lancaster or take a line further east into the Forest of Bowland. After Lancaster it's: the A6 (Kendal/Shap), optional westerly excursion to enjoy some of the Lake District, or head up the Lune valley via Tebay before coming back towards the A6 at Shap or dropping into the Lyvennet, then Eden valleys heading north.
Penrith to Carlisle, then Longtown/Gretna (A7 or // M6): boring A6, Hutton End (racecourse) road or scenic Eden valley
In Scotland and going north.
Three main ways to get up to the Clyde/Forth line:
A. NW to Ardrossan and ferries to Kintyre via Isle of Arran.
B. // M74 to Glasgow (or pass east of the city)
C. N to Edinburgh (using south-going LEL route recommended)
A1. If A you're going 'West Coast' via Oban, Fort William, Great Glen
A11. to Dingwall (via Inverness or Beauly)
A12. 'West coast' to Durness via Ullapool (Note consider going from Oban via Mull , Ardnamurchan and Skye if heading for there)
B1. If B you could cut NE through Dunblane and Crieff to the A9 (to Inverness)
B2. Go north via Killin to the A9 (to Inverness)
B3. Head NW/NNW/N to the A82 (Loch Lomond) to Fort William
B4. Option of the Gourock/Dunoon ferry and 'west coast' via Connel or back to the A82 to Fort William
C1. If C, you're logically heading for Perth, the A9 and Inverness
C2. Tho' maybe via Braemar for some scenery (and to stay off the A9).
After the Moray/Cromarty Firths, three options:
a. Long tour round the west coast via Durness (see A12 above) and east to JoG
b. A9 up the east coast
c. N thro' Lairg and Altnaharra to Bettyhill (and then east to JoG), either via Tongue or Strathnaver
My route was this one:
https://ridewithgps.com/routes/8592623
Main preference for me was not to ride long distances on the A9 (the lot of the 'East Coast' warrior), or the A82: had to do some from Corran ferry to Ft William (Banavie) and from the Commando memorial (Spean Bridge) to Drumnadrochit but dived off all I could on parallel roads/towpaths (eg from Banavie and from Bridge of Oich to Ft Augustus).
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