I have become absolutely hooked since discovering OS Maps - it has revolutionised my walk planning and made it a complete pleasure. Therefore I’ve used it for the last 4 walks I’ve planned. It very neatly solves the 'originality problem' because you can be sure to choose nice wooded or countrified areas away from busy roads. It also enables you to find some paths undiscoverable to the naked eye, which is guaranteed to make your route interesting and one-of-a-kind (don't forget to reccie it first though). The 'distance problem' is solved because OS Maps measures your route as you go, so no more pieces of string and rulers required!
Anyway, in classic Blue Peter style, here’s one I prepared earlier - which is my next walk around Molash on the 28th Feb 2016:
OS Maps enables you to browse on your computer any Ordnance Survey maps at 1:50,000 or 1:25,000 zoom level and draw your own route. As you plan your route, it calculates your distance and the estimated time, so you know whether you are going to be back to the pub on time - and not too quickly either, as we don’t want EKWGers feeling short-changed on their promised mileage do we?
For the next steps, I’m making the assumption that you’ll do your route planning on a desktop PC, laptop or Mac - they all work roughly the same.
Enter the starting point (e.g. postcode) in the top left hand box and click the search magnifying glass:
Once your location has been found, click on the icon that appears on the map and click More info on the popup.
panel appear on the left hand side with a Create route link you should click:
Once you are done with the route planning part and you’ve got clicked your walk route back to the beginning again, you can click 
on the toolbar along the top and then you’ll be prompted for the description and difficulty and that’s it.
Now, read on to the next section about and following your route...
Regarding the actual route following part, once you are geographically in your walking area, you will see a moving ‘pointer’ that represents ‘you’ in your current position. When you begin your walk you will then be able to see whether you are ‘on track’ or not and make the necessary adjustments to your path!
That last point is probably what I love so much about mobile navigation - you get real-time feedback from your progress. Generally speaking I can tell if I’ve gone off my route by the time I've walked a hundred feet or so because I will see the pointer diverging from the route line. So I can very quickly make corrections and get back on track without the rest of my EKWG party being any the wiser! I find this so much easier than with a paper map because with the latter you are never really sure where you currently are (Okay, well it might just be me with that problem then?). As a result, I no longer take a paper map with me. What is really important however, is being fully prepared with backup phone charging facilities. An iPhone can easily become flat if it's being used full-time for navigation during even a 4 hour walks. I'll now explain about the mobile charging setup I use.
There are many devices on the market but I am very happy with the EC Technology 3 USB Output External Battery which is shown below.
Just pop the charger and a phone cable charger in your backpack on your walk. When your battery begins to get low, just plug it in and you will get up to 10 charges from this before the pack will itself need recharging (it comes with a mains adapter). NOTE: If you need more than 10 charges during one walk then something will probably have gone terribly wrong with your walk, and I can't help you with that I'm afraid.
Nick - April 2016