Hi,
Driving in Scotland:-
Allow much more time for a route than you would elsewhere! Most "A" routes are ok, but tend to be two lanes - one in each direction. Overtaking opportunities are available - if you're lucky! Remember that the HGVs have a 40mph speed limit, regardless of the actual signposted one.
Do take a SatNav - up in the Highlands mobile phone signals can be elusive (we had to ferry a couple of tourists 20 miles so they could phone for hire car help - tyre blowout and no spare in the hirecar).
Fortunately, there are no "A" roads which are single track with passing places now - beware of the "B" roads, some are still single track. Avoid those with grass in the middle.
Scottish drink/driving law is stricter than English, so check carefully.
Depending on your beer preference, there are some great craft beers in Scotland, avoid the Tennants and remember that beer is sold in imperial pints and half-life (20 fl Oz or 10 fl Oz - larger than US pints).
Spirits are in 25 ml increments (avoiding the old problem of 1/5 gill in England and 1/4 gill in Scotland).
For music, look out for fiddle rallies, Highland games and individual flyers/pub notices.
Lastly, if you have any problems, ask a local (on the lines of "we're on holiday and from xxxx - insert country - can you help us?). ie identify yourself as not English, there's a long memory in parts, and still some ill feeling. Above all else, remember to use Scotland, Scots don't use England, English unless you mean the country to the south!
Enjoy!
Colin
Edited to correct autocorrect - it turned "gill" into "bill", obviously not knowing imperial liquid measures!