As a new arrival to the UK, I was recently asking a Scottish colleague in the Royal Marines about hiking trips in Scotland. Below was his response to my request for some loops that I could do if I drove up from London. They might give you some ideas.
There are four recognised long walks in Scotland (ie signposted etc) – The West Highland Way (95 miles), The Southern Upland Way (212 miles), The Great Glen Way (73 miles) and The Speyside Way (65 miles). These are easy to find out information about (I’m sure Google will lead you to them). These are all one way routes unless you double back on yourself but where is the fun in that!
There are some interesting routes elsewhere:
1. The Four Highest is about 30 mile circular route starting from Cairngorm Youth Hostel.
2. Blair Atholl/Aviemore Figure of 8 is about 110miles and can start and finish in the same place – either Blair Atholl, Cairngorm Youth Hostel (can be linked with the Four Highest Route above) or Inverey Youth Hostel.
3. Glen Etive and Rannoch Moor is about 90 mile route but requires a train drop off as it is not circular – Rannoch station or Corrour Station are suitable.
4. Knoydart is a 100 mile circular route starting at Alltbeithe Youth Hostel.
5. Loch Mullardoch is another nice little 40 miler circular route going the other way from Alltbeithe Youth Hostel so can be linked to the Knoydart route above.
6. Loch Monar is a 65 mile circular route starting at Scardroy Lodge.
I would say routes 1, 5 and 6 are ‘easy going’ but would say that routes 2, 4 and especially 3 are a little more tricky. There is nothing that would stop an experienced walker – just make sure you have your compass with you!
Edit - and additional link that you might find useful.