Never done LeJog but when I stared touring there were no electronic devices. We used a road map from a filling station and on one occasion I left it behind at Inveraray hostel but just carried on regardless. Mind you the road systems were less complicated so far as main roads were concerned. No reason why it should not be done with no electronics.
Yes, I did JoGLE in the pre-smartphone era, had an NCN guidebook with a map of northern Scotland which allowed me to bypass most of the A9.
Relying on the sun for navigation in Scotland is a remarkably poor idea, for reasons that are clear to anyone who has ever been here. I think I saw it once between JoG and Glasgow...Never have the sun in your eyes and you must be heading, generally, northwards..
Then turn right at Bettyhill