I'd suggest trying the 'scenario' flights on the FS flights menu. They're pretty well graded to be 'Easy,' 'Medium', or 'Hard' - and they take you to all sorts of interesting places.
The routes are pre-determined, and the scenarios are set up in specific (often quite challenging) weather. They mainly consist of a series of pre-planned flights, set up for specific aeroplanes; but you'll find that you can substitute any other aircraft at will.
'Hawaian Vacation' is a cinch. 'Frontier Airlines,' and 'European Airline Pilot' are pretty straightforward. 'Aerial Chauffeur' is my particular favourite, starts off pretty easy but gets very challenging towards the end. You have to be pretty good to finish 'Reeve Aleutian Airlines' in one piece, even if you use a modern type instead of the DC3 it's designed for.

