I've done Bergen direct to Aberdeen in a 1940's vintage single, never venturing above 100 feet awl because it was a clear blue beuatiful horizon and I loved the sensation of flying low. Watch for the oil rigs! and the helicopters which are above you.
No AI, no Turn and slip, no autopilot. Just GPS and a compass & stopwatch. Check the forecast ahead for fog etc.
If the engine quits (which it wont if theres enough fuel and oil and you don't fiddle with anything) then hard cheese, but life is too short to worry about that kind of thing. One of my best flying expeiences.
Russ
p.s. I'm older & wiser now, so would not do it again, unless sutably persuaded.