My partner and I recently walked part of the West Highland Way in Scotland. The total length of the long distance walk is 151km from Milngavie on the edge of Glasgow to Fort William at the foot of Ben Nevis. We covered about half the distance, starting from Rowardennan and walking a total of five days with two rest days in between.
We left London on the Caledonian Sleeper train at 23:50 on Thursday evening and got to Glasgow Central at 07:20 after a surprisingly good sleep in our little sleeper cabin. You get woken up with your choice of tea or coffee in the morning!
We then took a train from Glasgow Queen Street station to Tarbet which got us to the shores of Loch Lomond at 09:40. We caught the 10:00 ferry from Tarbet to Rowardennan on the other side of the Loch and began our walk around 11:00, less than 12 hours after leaving London.