There are numerous mapping options to help with initial planning and creation of GPS files or printed maps - as well as creating routes*
Listed here, in alphabetical order, is a wide range of services/software/gadgets with links to them (opening in new windows) - some are free, some have a subscription charge, some work with a web browser, some work with an Android or iPhone, some have the facility to convert from one format to another - .gpx is the most common format.
There are also many apps for both Android and iPhone gadgets, mostly based on OpenStreetMaps or Google Maps.
Bike Ride Maps - https://www.bikeridemaps.co.uk
Bikehike http://bikehike.co.uk
Bikemap https://www.bikemap.net/en/routeplanner/
Bryton (GPS gadget with mapping) https://www.brytonsport.com/
Garmin (GPS gadget with mapping) garmin.com
Garmin Connect https://connect.garmin.com/
Google Maps (and Streetview) https://www.google.com/maps
Google Maps (convert route to .gpx) https://mapstogpx.com/
GPS Visualiser (format converter) http://www.gpsvisualizer.com
Just Go Ride https://www.justgoride.co.uk/
Komoot https://www.komoot.com
Memory Map - PC based mapping and route creation https://memory-map.com/
Mio (GPS gadget with mapping) https://www.mio.com
OnTheGoMap https://www.mio.com
OpenStreetMaps - free mapping https://www.openstreetmap.org/#m
Ordnance Survey https://www.ordnancesurvey.co.uk/
Osola (load .gpx to maps) https://www.osola.org.uk/rides/gpsuploader.htm
Plotaroute https://www.plotaroute.com
Ride with GPS http://ridewithgps.com/
RouteYou https://www.routeyou.com/en-gb
Strava (Ride recording/competition, with separate mapping capability) https://strava.com
Strava .gpx upload https://labs.strava.com/
Via Michelin https://www.viamichelin.co.uk/
Viewranger https://www.viewranger.com/en-gb
Wahoo (GPS gadget with mapping) https://uk.wahoofitness.com
* my experience with services that offer "here to there" routing has been mixed - the results need to be checked to ensure that the route uses suitable roads/lanes (offering motorways or drover tracks isn't unusual!)
There are also errors in many of the base mapping with roads marked that don't exist, and roads that exist not marked - using Google Streetview is a good way to check if you're in doubt.
The list here is not definitive and is with no recommendation or warranty.
.oOo.
Books
In no particular order this is a listing of books about riding the End-to-End in the UK together with some other books and mapping resources. There are others . . .
End to End Cycle Guide - Land's End to John o'Groats : Cicerone Guide
A handy guidebook describing a 14-day End to End cycle route from Land's End to John o' Groats (LEJOG), largely on minor roads and cycle paths, with detailed maps, profiles, all key grid refs and GPX files. Also full listings of accommodation providers, tourist information offices and bike shops as well as tips for first-time cycle tourers.
A very good source of information - probably the most used route. The following is the product description from Amazon Books:
This handy pocket guidebook offers a detailed route description of an End to End cycle route from Land's End to John o' Groats, with over 350 OS grid refs included for GPS navigation. It is divided into 14 stages and contains information on where to stay, with full details of numerous B&Bs, campsites, cycle shops, small hotels, tourist information offices and hostels. The route has been designed to avoid the busier A roads as much as possible and follow minor roads and cycle paths. It also takes in some of the best landscapes of Britain from Dartmoor, the Wye Valley and the Welsh Marches, the Forest of Bowland, the Lake District through to the glorious Strathnaver Trail and the rugged coast of Caithness. Descriptions of key landmarks along the route are also included, from Tintern Abbey through to the Forth and Clyde Canal in Glasgow and beyond.
Bike Britain: Cycling from Land's End to John O'Groats : Epic Books
This book is out of print and only available second-hand at premium price
An excellent book, probably 85% of my E2E route was derived from this book. The following is the product description from Amazon Books:
Land's End to John O'Groats is Britain's classic long-distance cycle tour. This route, from the south-west tip of England to the north-east tip of Scotland, follows mostly quieter roads and incorporates some of Britain's most beautiful and interesting areas: the Cornish coast, the Roman towns of Bath and Chester, the Lake District and Scotland's tussock covered Highlands and brooding lochs. Whether cyclists are planning a short county to county jaunt, or a tip to tip epic, they will find this unique guide valuable. The volume features: the best times to go and what to take; detailed route descriptions, including historic and geographic data; strip maps, elevation profiles and GPS points along the route; hotel, B&B, hostel and camping ground listings; and information centres and bicycle shops.
Land's End to John O'Groats: The Great British Bike Adventure -
This book was out of print but is now available again ... the following is a review from Amazon Books (from 1999), I have to agree that it was pretty poor. The more recent version appears to be a modest improvement.
"I must admit, the introduction was by the far the best nine pages included in this book. I shared all of the author's 'dreams' covered within the introduction, only to be lead into a second rate history of Great Britain. Each of the towns/cities visited along the way were given a BRIEF historic review, not particularly relevant to the touring cyclist embarking on this mammoth trek. The maps were a little confusing and one must ask oneself if using two different shades of red for routes and major highways was a wise choice. Overall I have come to the conclusion that there was not enough relevant information in this text"
Lonely Planet Cycling Great Britain
Not just the E2E but lots of other routes too. The details are comprehensive but in common with most Lonely Planet books this one has an awful lot of the content taken up with general information about the country to pad it out.
Mapping
Memory Map
Ordnance Survey and other maps to use on a PC with comprehensive plotting and printing facilities; easy creation of files for GPS
The Map Shop, Upton-on-Severn
A fantastic source - they must have every map known to man!