Great Glen Way
The Great Glen Way is in Scotland.
The Great Glen Way is a 73 mile (118 kilometre) hike between Fort William and Inverness, in the Scottish Highlands. It follows a major geological fault that runs southwest-northeast across the width of Northern Scotland. The walk takes you past the famous Loch Ness, where you can scan the waters for the Loch Ness Monster.
It is generally recommended that you walk the route starting at Fort William and ending in Inverness, because this direction means you have the sun and the prevailing wind at your back the whole time. Fort William can be reached from Glasgow, Edinburgh, Newcastle, London and many other major British towns by train and bus. The train trip from London usually takes the better part of a day.
The walk passes through Gairlochy, Loch Lochy, Laggan, Fort Augustus, Invermoriston and Drumnadrochit. The last three are on the shores of Loch Ness There are also diversions along the route to the Commando Memorial at Spean Bridge, and several former castles/museums.
There are at least some accommodation options in each of the towns that the Great Glen Way passes through:
There are Tesco outlets at Fort William, Drumnadrochit and Inverness. Apart from this, if you need to buy supplies along the way you will need to plan ahead and pick them up at the first opportunity. Invermoriston has a small convenience/grocery shop. Fort Augustus has some good cafes and supermarkets. There are several guides for purchase, and at least one comprehensive website for the Great Glen Way, but it is possible to walk the route without a map (there are route markers at all key intervals) and without accommodation bookings.  
The usual precautions of Wilderness backpacking apply. Since you probably sleep in hostels and Bed & Breakfasts on the way, you don't need to carry as much supplies and gear (tents, sleeping bags) as when sleeping in the wild, however a sufficient supply of water and food for the day should be carried and you should always restock on first opportunity. You should carry warm and waterproof clothes with you, a good map and travel guide and a compass. A mobile phone is a good idea, but in remote areas there might be no coverage, so be warned. Midges are a nuisance during summer months, so use a good insect repellent as well as sunscreen.
If you call ahead accomodations to book a place for the night, remember to cancel the booking if you don't want to stay there anymore. If you don't show up although you told them, they might alarm the local rescue service thinking you are lost in the wild, although infact you are sleeping just at the place across the road.
The Great Glen Way has some fairly strenuous sections in which you are walking into or out of the valley, but most sections can be broken into 11 mile parts. It should take 4 to 6 days to complete. The official end/starting point of the walk is the Castle at Inverness.