Farthest North? Scottish Highlands, probably Inverness at the end of Loch Ness.
Farthest South? Orlando, FL.
Farthest East? Dar es Salaam, TZ.
Farthest West? Pacific Coast of California: Santa Barbara, probably.
Highest Elevation? Wheeler Peak was 13,161'. I may have been higher in a car driving around Pike's Peak or around Yellowstone.
Hottest Temp? Probably about 110 or 112 F. (Indiana boyhood).
Coldest Temp? I remember one cold day driving in Chicago when it was -26 F., with a wind chill of WTF; coldest camping was at least 16 below on a Klondike Derby at Camp Krietenstein, and might've been colder (it's been a long time).