Going to Scotland

The little Mrs and me are going to Scotland next week for 14 days, it's her 60th birthday trip.
We will be all over the northern half of the country, away from the big cities.
Anyone have any advice or travel tip's? Cool places to see etc.
Thanks in advance
Wife and I went last year w/ family; flew into Edinburgh and stayed a couple of days, then drove to Killen and finished out the week. Did a lot of hiking, lots of mountaintop trails w/ beautiful scenery. Visited the Dewars distillery, which was really interesting. Wow the roads are NARROW! Our rental car was a 6-speed stick diesel Ford minivan; way cool but took some getting used to, as well as driving on the other side of the road. Friendly people and good food and drink; had a great time and would go back in a heartbeat.