I’ve got an itinerary for a coastal tour of the UK, that includes the Shetlands, Orkneys and Inner/Outer Hebrides if you’re interested?
I’ve flown it at <1000ft in a C152 and it was great fun. It’s tough to get lost when you’re following the coast, unless you go the wrong way of course. 
UK simmers where you at?! - Multiplayer / Find a Friend - Microsoft Flight Simulator Forums
Just load it into a spreadsheet and you can start wherever you want. You might want to remove Manchester (EGCC) though, as that isn’t overly coastal and was added for a special request.